staging: r8188eu: use a qos_hdr in validate_recv_data_frame

Define a struct ieee80211_qos_hdr in the validate_recv_data_frame
function. Use this struct to replace some numeric offsets and make the
code easier to understand.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20221107202824.61431-2-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_recv.c

@@ -1032,7 +1032,6 @@ static int validate_recv_data_frame(struct adapter *adapter,
 				    struct recv_frame *precv_frame)
 {
 	struct sta_info *psta = NULL;
-	u8 *ptr = precv_frame->rx_data;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)precv_frame->rx_data;
 	struct rx_pkt_attrib	*pattrib = &precv_frame->attrib;
 	struct security_priv	*psecuritypriv = &adapter->securitypriv;
@@ -1071,10 +1070,12 @@ static int validate_recv_data_frame(struct adapter *adapter,
 	pattrib->ack_policy = 0;
 	/* parsing QC field */
 	if (pattrib->qos) {
+		struct ieee80211_qos_hdr *qos_hdr = (struct ieee80211_qos_hdr *)hdr;
+
 		pattrib->priority = ieee80211_get_tid(hdr);
-		pattrib->ack_policy = GetAckpolicy((ptr + 24));
-		pattrib->amsdu = GetAMsdu((ptr + 24));
-		pattrib->hdrlen = 26;
+		pattrib->ack_policy = GetAckpolicy(&qos_hdr->qos_ctrl);
+		pattrib->amsdu = GetAMsdu(&qos_hdr->qos_ctrl);
+		pattrib->hdrlen = sizeof(*qos_hdr);
 
 		if (pattrib->priority != 0 && pattrib->priority != 3)
 			adapter->recvpriv.bIsAnyNonBEPkts = true;