drm: provide agp dummies for CONFIG_AGP=n

We currently rely on gcc dead-code elimination so the drm_agp_* helpers
are not called if drm_core_has_AGP() is false. That's ugly as hell so
provide "static inline" dummies for the case that AGP is disabled.

Fixes a build-regression introduced by:

  commit 28ec711cd427f8b61f73712a43b8100ba8ca933b
  Author: David Herrmann <dh.herrmann@gmail.com>
  Date:   Sat Jul 27 16:37:00 2013 +0200

      drm/agp: move AGP cleanup paths to drm_agpsupport.c

v2: switch #ifdef -> #if (spotted by Stephen)

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index fba5473..3ecdde6 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -62,10 +62,8 @@
 #endif
 #include <asm/mman.h>
 #include <asm/uaccess.h>
-#if defined(CONFIG_AGP) || defined(CONFIG_AGP_MODULE)
 #include <linux/types.h>
 #include <linux/agp_backend.h>
-#endif
 #include <linux/workqueue.h>
 #include <linux/poll.h>
 #include <asm/pgalloc.h>
@@ -1226,16 +1224,6 @@
 	return dev->driver->bus->get_irq(dev);
 }
 
-
-#if __OS_HAS_AGP
-static inline int drm_core_has_AGP(struct drm_device *dev)
-{
-	return drm_core_check_feature(dev, DRIVER_USE_AGP);
-}
-#else
-#define drm_core_has_AGP(dev) (0)
-#endif
-
 #if __OS_HAS_MTRR
 static inline int drm_core_has_MTRR(struct drm_device *dev)
 {
@@ -1292,14 +1280,6 @@
 
 				/* Memory management support (drm_memory.h) */
 #include <drm/drm_memory.h>
-extern void drm_free_agp(DRM_AGP_MEM * handle, int pages);
-extern int drm_bind_agp(DRM_AGP_MEM * handle, unsigned int start);
-extern DRM_AGP_MEM *drm_agp_bind_pages(struct drm_device *dev,
-				       struct page **pages,
-				       unsigned long num_pages,
-				       uint32_t gtt_offset,
-				       uint32_t type);
-extern int drm_unbind_agp(DRM_AGP_MEM * handle);
 
 				/* Misc. IOCTL support (drm_ioctl.h) */
 extern int drm_irq_by_busid(struct drm_device *dev, void *data,
@@ -1453,33 +1433,8 @@
 			   struct drm_file *file_priv);
 
 				/* AGP/GART support (drm_agpsupport.h) */
-extern struct drm_agp_head *drm_agp_init(struct drm_device *dev);
-extern void drm_agp_destroy(struct drm_agp_head *agp);
-extern void drm_agp_clear(struct drm_device *dev);
-extern int drm_agp_acquire(struct drm_device *dev);
-extern int drm_agp_acquire_ioctl(struct drm_device *dev, void *data,
-				 struct drm_file *file_priv);
-extern int drm_agp_release(struct drm_device *dev);
-extern int drm_agp_release_ioctl(struct drm_device *dev, void *data,
-				 struct drm_file *file_priv);
-extern int drm_agp_enable(struct drm_device *dev, struct drm_agp_mode mode);
-extern int drm_agp_enable_ioctl(struct drm_device *dev, void *data,
-				struct drm_file *file_priv);
-extern int drm_agp_info(struct drm_device *dev, struct drm_agp_info *info);
-extern int drm_agp_info_ioctl(struct drm_device *dev, void *data,
-			struct drm_file *file_priv);
-extern int drm_agp_alloc(struct drm_device *dev, struct drm_agp_buffer *request);
-extern int drm_agp_alloc_ioctl(struct drm_device *dev, void *data,
-			 struct drm_file *file_priv);
-extern int drm_agp_free(struct drm_device *dev, struct drm_agp_buffer *request);
-extern int drm_agp_free_ioctl(struct drm_device *dev, void *data,
-			struct drm_file *file_priv);
-extern int drm_agp_unbind(struct drm_device *dev, struct drm_agp_binding *request);
-extern int drm_agp_unbind_ioctl(struct drm_device *dev, void *data,
-			  struct drm_file *file_priv);
-extern int drm_agp_bind(struct drm_device *dev, struct drm_agp_binding *request);
-extern int drm_agp_bind_ioctl(struct drm_device *dev, void *data,
-			struct drm_file *file_priv);
+
+#include <drm/drm_agpsupport.h>
 
 				/* Stub support (drm_stub.h) */
 extern int drm_setmaster_ioctl(struct drm_device *dev, void *data,