staging: rtl8712: Remove unnecessary parentheses.

Removed unnecessary parentheses around pointers to fix the following
checkpatch issues:

CHECK: Unnecessary parentheses around padapter->xmitpriv
CHECK: Unnecessary parentheses around padapter->recvpriv

Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>