drm/core: add ioctl to query device/driver capabilities

We're coming to see a need to have a set of generic capability checks in
the core DRM, in addition to the driver-specific ioctls that already
exist.

This patch defines an ioctl to do as such, but does not yet define any
capabilities.

[airlied: drop the driver callback for now.]

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 52a2fd2..8352147 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1276,6 +1276,8 @@
 			 struct drm_file *file_priv);
 extern int drm_getstats(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
+extern int drm_getcap(struct drm_device *dev, void *data,
+		      struct drm_file *file_priv);
 extern int drm_setversion(struct drm_device *dev, void *data,
 			  struct drm_file *file_priv);
 extern int drm_noop(struct drm_device *dev, void *data,