Staging: rtl8723au: core: Fix unnecassary braces warning.

This patch fixes these warning messages found by checkpatch.pl:
WARNING: braces {} are not necessary for single statement blocks

Signed-off-by: Aybuke Ozdemir <aybuke.147@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>