[BLUETOOTH]: Introduce skb->data accessor methods for hci_{acl,event,sco}_hdr

For consistency with other skb data accessors, reducing the number of direct
accesses to skb->data.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/drivers/bluetooth/bt3c_cs.c b/drivers/bluetooth/bt3c_cs.c
index 18b0f39..3951607 100644
--- a/drivers/bluetooth/bt3c_cs.c
+++ b/drivers/bluetooth/bt3c_cs.c
@@ -303,20 +303,20 @@
 				switch (info->rx_state) {
 
 				case RECV_WAIT_EVENT_HEADER:
-					eh = (struct hci_event_hdr *)(info->rx_skb->data);
+					eh = hci_event_hdr(info->rx_skb);
 					info->rx_state = RECV_WAIT_DATA;
 					info->rx_count = eh->plen;
 					break;
 
 				case RECV_WAIT_ACL_HEADER:
-					ah = (struct hci_acl_hdr *)(info->rx_skb->data);
+					ah = hci_acl_hdr(info->rx_skb);
 					dlen = __le16_to_cpu(ah->dlen);
 					info->rx_state = RECV_WAIT_DATA;
 					info->rx_count = dlen;
 					break;
 
 				case RECV_WAIT_SCO_HEADER:
-					sh = (struct hci_sco_hdr *)(info->rx_skb->data);
+					sh = hci_sco_hdr(info->rx_skb);
 					info->rx_state = RECV_WAIT_DATA;
 					info->rx_count = sh->dlen;
 					break;