rtlwifi: access skb->data to get C2H data by macro

The format of C2H data is ID(1 byte) + Length(1 byte) + value, and it is
more readable to use macros to access C2H data.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtlwifi/base.c

@@ -2288,10 +2288,10 @@ static void rtl_c2h_content_parsing(struct ieee80211_hw *hw,
 	u8 cmd_id, cmd_seq, cmd_len;
 	u8 *cmd_buf = NULL;
 
-	cmd_id = skb->data[0];
-	cmd_seq = skb->data[1];
-	cmd_len = skb->len - 2;
-	cmd_buf = skb->data + 2;
+	cmd_id = GET_C2H_CMD_ID(skb->data);
+	cmd_seq = GET_C2H_SEQ(skb->data);
+	cmd_len = skb->len - C2H_DATA_OFFSET;
+	cmd_buf = GET_C2H_DATA_PTR(skb->data);
 
 	switch (cmd_id) {
 	case C2H_DBG:

drivers/net/wireless/realtek/rtlwifi/wifi.h

@@ -177,6 +177,11 @@ enum rtl_c2h_evt_v2 {
 	C2H_V2_CCX_RPT = 0x0F,
 };
 
+#define GET_C2H_CMD_ID(c2h)	({u8 *__c2h = c2h; __c2h[0]; })
+#define GET_C2H_SEQ(c2h)	({u8 *__c2h = c2h; __c2h[1]; })
+#define C2H_DATA_OFFSET		2
+#define GET_C2H_DATA_PTR(c2h)	({u8 *__c2h = c2h; &__c2h[C2H_DATA_OFFSET]; })
+
 #define GET_TX_REPORT_SN_V1(c2h)	(c2h[6])
 #define GET_TX_REPORT_ST_V1(c2h)	(c2h[0] & 0xC0)
 #define GET_TX_REPORT_RETRY_V1(c2h)	(c2h[2] & 0x3F)