drm/shmem: switch shmem helper to &drm_gem_object_funcs.mmap

Switch gem shmem helper to the new mmap() workflow,
from &gem_driver.fops.mmap to &drm_gem_object_funcs.mmap.

v2: Fix vm_flags and vm_page_prot handling.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20191016115203.20095-3-kraxel@redhat.com

include/drm/drm_gem_shmem_helper.h

@@ -111,7 +111,7 @@ struct drm_gem_shmem_object {
 		.poll		= drm_poll,\
 		.read		= drm_read,\
 		.llseek		= noop_llseek,\
-		.mmap		= drm_gem_shmem_mmap, \
+		.mmap		= drm_gem_mmap, \
 	}
 
 struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size);
@@ -143,9 +143,7 @@ drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
 int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
 			      struct drm_mode_create_dumb *args);
 
-int drm_gem_shmem_mmap(struct file *filp, struct vm_area_struct *vma);
-
-extern const struct vm_operations_struct drm_gem_shmem_vm_ops;
+int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
 
 void drm_gem_shmem_print_info(struct drm_printer *p, unsigned int indent,
 			      const struct drm_gem_object *obj);