Staging: rtl8723au: remove unnecessary break after return

WARNING: break is not useful after a goto or return.
Remove unnecessary break after return. That was found by running checkpatch.

Signed-off-by: Melike Yurtoglu <aysemelikeyurtoglu@gmail.com>
Reviewed-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>