staging: r8712u: Fix Sparse endian warning in rtl871x_recv.c

Sparse reports the following:
  CHECK   drivers/staging/rtl8712/rtl871x_recv.c
drivers/staging/rtl8712/rtl871x_recv.c:657:21: warning: incorrect type in assignment (different base types)
drivers/staging/rtl8712/rtl871x_recv.c:657:21:    expected unsigned short [unsigned] [assigned] [usertype] len
drivers/staging/rtl8712/rtl871x_recv.c:657:21:    got restricted __be16 [usertype] <noident>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8712/rtl871x_recv.c

@@ -654,8 +654,9 @@ sint r8712_wlanhdr_to_ethhdr(union recv_frame *precvframe)
 	memcpy(ptr, pattrib->dst, ETH_ALEN);
 	memcpy(ptr + ETH_ALEN, pattrib->src, ETH_ALEN);
 	if (!bsnaphdr) {
-		len = htons(len);
-		memcpy(ptr + 12, &len, 2);
+		__be16 be_tmp = htons(len);
+
+		memcpy(ptr + 12, &be_tmp, 2);
 	}
 	return _SUCCESS;
 }