drm/vmwgfx: Implement screen targets

Add support for the screen target device interface.
Add a getparam parameter and bump minor to signal availability.

Signed-off-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
diff --git a/include/uapi/drm/vmwgfx_drm.h b/include/uapi/drm/vmwgfx_drm.h
index c472bedb..c8a8631 100644
--- a/include/uapi/drm/vmwgfx_drm.h
+++ b/include/uapi/drm/vmwgfx_drm.h
@@ -88,6 +88,7 @@
 #define DRM_VMW_PARAM_3D_CAPS_SIZE     8
 #define DRM_VMW_PARAM_MAX_MOB_MEMORY   9
 #define DRM_VMW_PARAM_MAX_MOB_SIZE     10
+#define DRM_VMW_PARAM_SCREEN_TARGET    11
 
 /**
  * enum drm_vmw_handle_type - handle type for ref ioctls