Fixed unknown RAT in IWLAN registration info

When modem crashes, the IWLAN registration info in
service state should be reset to unknown. Also add
another check in data network to make sure we don't
send unknown access network type to IWLAN data service.

Bug: 224832687
Test: Manual
Merged-In: Ia7406fbe50983a4cf5d0d040701c16655a2f87fc
Change-Id: Ia7406fbe50983a4cf5d0d040701c16655a2f87fc