staging: rtl8712: used a better macro

Fixed a sparse warning.
Using be16_to_cpus() to avoid double assignment.
Signed-off-by: Jannik Becher <becher.jannik@gmail.com>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8712/rtl871x_recv.c

@@ -258,7 +258,7 @@ union recv_frame *r8712_portctrl(struct _adapter *adapter,
 		/* get ether_type */
 		ptr = ptr + pfhdr->attrib.hdrlen + LLC_HEADER_SIZE;
 		memcpy(&ether_type, ptr, 2);
-		ether_type = ntohs((unsigned short)ether_type);
+		be16_to_cpus(&ether_type);
 
 		if ((psta != NULL) && (psta->ieee8021x_blocked)) {
 			/* blocked