Add wpa_bss_get_max_rate() to match with old scan_res helpers

wpa_supplicant/bss.c

@@ -356,3 +356,25 @@ struct wpabuf * wpa_bss_get_vendor_ie_multi(const struct wpa_bss *bss,
 
 	return buf;
 }
+
+
+int wpa_bss_get_max_rate(const struct wpa_bss *bss)
+{
+	int rate = 0;
+	const u8 *ie;
+	int i;
+
+	ie = wpa_bss_get_ie(bss, WLAN_EID_SUPP_RATES);
+	for (i = 0; ie && i < ie[1]; i++) {
+		if ((ie[i + 2] & 0x7f) > rate)
+			rate = ie[i + 2] & 0x7f;
+	}
+
+	ie = wpa_bss_get_ie(bss, WLAN_EID_EXT_SUPP_RATES);
+	for (i = 0; ie && i < ie[1]; i++) {
+		if ((ie[i + 2] & 0x7f) > rate)
+			rate = ie[i + 2] & 0x7f;
+	}
+
+	return rate;
+}

wpa_supplicant/bss.h

@@ -79,5 +79,6 @@ const u8 * wpa_bss_get_ie(const struct wpa_bss *bss, u8 ie);
 const u8 * wpa_bss_get_vendor_ie(const struct wpa_bss *bss, u32 vendor_type);
 struct wpabuf * wpa_bss_get_vendor_ie_multi(const struct wpa_bss *bss,
 					    u32 vendor_type);
+int wpa_bss_get_max_rate(const struct wpa_bss *bss);
 
 #endif /* BSS_H */