Interworking: Fix PLMN matching with multiple entries

The pos variable was not advanced when comparing PLMN entries in
3GPP Cellular Network information and as such, only the first
entry was really used.

Signed-hostap: Jouni Malinen <j@w1.fi>
intended-for: hostap-1

wpa_supplicant/interworking.c

@@ -551,6 +551,7 @@ static int plmn_id_match(struct wpabuf *anqp, const char *imsi, int mnc_len)
 					break;
 				if (os_memcmp(pos, plmn, 3) == 0)
 					return 1; /* Found matching PLMN */
+				pos += 3;
 			}
 		}