drm: kill ->gem_init_object() and friends

All drivers embed gem-objects into their own buffer objects. There is no
reason to keep drm_gem_object_alloc(), gem->driver_private and
->gem_init_object() anymore.

New drivers are highly encouraged to do the same. There is no benefit in
allocating gem-objects separately.

Cc: Dave Airlie <airlied@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Ben Skeggs <skeggsb@gmail.com>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/udl/udl_drv.c

@@ -77,7 +77,6 @@ static struct drm_driver driver = {
 	.unload = udl_driver_unload,
 
 	/* gem hooks */
-	.gem_init_object = udl_gem_init_object,
 	.gem_free_object = udl_gem_free_object,
 	.gem_vm_ops = &udl_gem_vm_ops,
 

drivers/gpu/drm/udl/udl_drv.h

@@ -115,7 +115,6 @@ int udl_dumb_create(struct drm_file *file_priv,
 int udl_gem_mmap(struct drm_file *file_priv, struct drm_device *dev,
 		 uint32_t handle, uint64_t *offset);
 
-int udl_gem_init_object(struct drm_gem_object *obj);
 void udl_gem_free_object(struct drm_gem_object *gem_obj);
 struct udl_gem_object *udl_gem_alloc_object(struct drm_device *dev,
 					    size_t size);

drivers/gpu/drm/udl/udl_gem.c

@@ -107,13 +107,6 @@ int udl_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	}
 }
 
-int udl_gem_init_object(struct drm_gem_object *obj)
-{
-	BUG();
-
-	return 0;
-}
-
 static int udl_gem_get_pages(struct udl_gem_object *obj, gfp_t gfpmask)
 {
 	struct page **pages;