drm/hisilicon: hibmc: Don't overwrite fb helper surface depth

Currently the driver overwrites the surface depth provided by the fb
helper to give an invalid bpp/surface depth combination.

This has been exposed by commit 70109354fed2 ("drm: Reject unknown legacy
bpp and depth for drm_mode_addfb ioctl"), which now causes the driver to
fail to probe.

Fix by not overwriting the surface depth.

Fixes: d1667b86795a ("drm/hisilicon/hibmc: Add support for frame buffer")
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Xinliang Liu <z.liuxinliang@hisilicon.com>
Signed-off-by: Xinliang Liu <z.liuxinliang@hisilicon.com>

drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_fbdev.c

@@ -71,7 +71,6 @@ static int hibmc_drm_fb_create(struct drm_fb_helper *helper,
 	DRM_DEBUG_DRIVER("surface width(%d), height(%d) and bpp(%d)\n",
 			 sizes->surface_width, sizes->surface_height,
 			 sizes->surface_bpp);
-	sizes->surface_depth = 32;
 
 	bytes_per_pixel = DIV_ROUND_UP(sizes->surface_bpp, 8);