NFC: Add tx skb allocation routine

This is a factorization of the current rawsock tx skb allocation routine,
as it will be used by the LLCP code.
We also rename nfc_alloc_skb to nfc_alloc_recv_skb for consistency sake.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/nfc/pn533.c

@@ -1368,7 +1368,7 @@ static int pn533_data_exchange(struct nfc_dev *nfc_dev, u32 target_idx,
 			PN533_CMD_DATAEXCH_DATA_MAXLEN +
 			PN533_FRAME_TAIL_SIZE;
 
-	skb_resp = nfc_alloc_skb(skb_resp_len, GFP_KERNEL);
+	skb_resp = nfc_alloc_recv_skb(skb_resp_len, GFP_KERNEL);
 	if (!skb_resp) {
 		rc = -ENOMEM;
 		goto error;