vmwgfx: Fix unitialized stack read in vmw_setup_otable_base

One of the error paths in vmw_setup_otable_base causes us to return with
'ret' having never been set to anything causing us to return whatever was
on the stack.

Found with Coverity
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>

drivers/gpu/drm/vmwgfx/vmwgfx_mob.c

@@ -134,6 +134,7 @@ static int vmw_setup_otable_base(struct vmw_private *dev_priv,
 	cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 	if (unlikely(cmd == NULL)) {
 		DRM_ERROR("Failed reserving FIFO space for OTable setup.\n");
+		ret = -ENOMEM;
 		goto out_no_fifo;
 	}