staging: rtl8712: Fix unnecessary parentheses style warning

This fixes the following checkpatch.pl warning:

drivers/staging/rtl8712/rtl871x_recv.c:634 warning: Unnecessary parentheses - maybe == should be = ?

Signed-off-by: Yeliz Taneroglu <yeliztaneroglu@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>