staging: rtl8712: Remove unnecessary parentheses.

Remove unnecessary parentheses from rtl871x_cmd.c

Signed-off-by: Gulsah Kose <gulsah.1004@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>