Add TMOUS LTE APN

This is taken from the OTA update for the Note II.
All APNs are currently resolving to the same 2 addresses from my T-Mobile phone.
The T-Mobile support website lists fast.tmobile.com (no hyphen).
I am attempting to mirror the stock OTA from T-Mobile.

Change-Id: I863b517be7dec19620b79fc876a88ba65e4dacba

prebuilt/common/etc/apns-conf.xml

@@ -567,6 +567,7 @@
   <apn carrier="T-Mobile US 240" mcc="310" mnc="240" apn="epc.tmobile.com" user="none" password="none" server="*" mmsc="http://mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
   <apn carrier="T-Mobile US 250" mcc="310" mnc="250" apn="epc.tmobile.com" user="none" password="none" server="*" mmsc="http://mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
   <apn carrier="T-Mobile US" mcc="310" mnc="260" apn="epc.tmobile.com" user="none" password="none" server="*" mmsc="http://mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
+  <apn carrier="T-Mobile US LTE" mcc="310" mnc="260" apn="fast.t-mobile.com" user="none" password="none" server="*" mmsc="http://mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
   <apn carrier="Simple" mcc="310" mnc="260" apn="simple" mmsc="http://smpl.mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
   <apn carrier="StraightTalk T-Mobile" mcc="310" mnc="260" apn="wap.tracfone" port="8080" mmsc="http://mmsc.tracfone.com" type="default,supl,mms" />
   <apn carrier="T-Mobile US 270" mcc="310" mnc="270" apn="epc.tmobile.com" user="none" password="none" server="*" mmsc="http://mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />