gta4xl: use correct default network mode (4G)

Change-Id: I2b6d81ccd4d9cb9fdd28ca9f0fe9b8ae3dd9b25d
diff --git a/vendor.prop b/vendor.prop
index 926ebc5..0a68f38 100644
--- a/vendor.prop
+++ b/vendor.prop
@@ -1,6 +1,7 @@
 ### RIL
 ro.carrier=unknown
 ro.radio.noril=no
+ro.telephony.default_network=9
 ro.vendor.multisim.simslotcount=1
 persist.radio.multisim.config=ss
 vendor.rild.libpath=/vendor/lib64/libsec-ril.so