staging: rtl8712: braces should be used on all arms

Fix all instances of the following checkpatch.pl check:
CHECK: braces {} should be used on all arms of this statement

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>