staging: rtl8723au: rtw_restruct_wmm_ie23a(): Use cfg80211_find_vendor_ie()

Rewrite rtw_restruct_wmm_ie23a() using cfg80211_find_vendor_ie()
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723au/core/rtw_mlme.c

@@ -1911,31 +1911,23 @@ int rtw_set_key23a(struct rtw_adapter *adapter,
 int rtw_restruct_wmm_ie23a(struct rtw_adapter *adapter, u8 *in_ie,
 			   u8 *out_ie, uint in_len, uint initial_out_len)
 {
-	unsigned int ielength = 0;
-	unsigned int i, j;
+	int ielength;
+	const u8 *p;
 
-	i = 0; /* after the fixed IE */
-	while (i < in_len) {
 	ielength = initial_out_len;
 
-		/* WMM element ID and OUI */
-		if (in_ie[i] == 0xDD && in_ie[i + 2] == 0x00 &&
-		    in_ie[i + 3] == 0x50 && in_ie[i + 4] == 0xF2 &&
-		    in_ie[i + 5] == 0x02 && i+5 < in_len) {
+	p = cfg80211_find_vendor_ie(WLAN_OUI_MICROSOFT,
+				    WLAN_OUI_TYPE_MICROSOFT_WMM,
+				    in_ie, in_len);
 
-			/* Append WMM IE to the last index of out_ie */
-                        for (j = i; j < i + 9; j++) {
-				out_ie[ielength] = in_ie[j];
-				ielength++;
-                        }
-                        out_ie[initial_out_len + 1] = 0x07;
-                        out_ie[initial_out_len + 6] = 0x00;
-                        out_ie[initial_out_len + 8] = 0x00;
+	if (p && p[1]) {
+		memcpy(out_ie + initial_out_len, p, 9);
 
-			break;
-		}
+		out_ie[initial_out_len + 1] = 7;
+		out_ie[initial_out_len + 6] = 0;
+		out_ie[initial_out_len + 8] = 0;
 
-		i += (in_ie[i + 1] + 2); /*  to the next IE element */
+		ielength += 9;
 	}
 
 	return ielength;