All drm_fb_helper_restore_fbdev_mode() call sites, save one, do the same
locking.  Simplify this into drm_fb_helper_restore_fbdev_mode_unlocked().
Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>