drm/vmwgfx: Fix an overlay lockdep error

Fix a circular locking dependency between
struct vmw_overlay::mutex and
struct vmw_private::reservation_sem

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

diff --cc drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
Simple merge