To fix fatal exception in system process due to NullPointerException.

Null pointer check added to avoid NullPointerException, that was
leading fatal exception in system process hence framework rebooting.

Change-Id: Ia83a6178bd575954345020ef3a792a3445323808
CRs-fixed: 483763
Revert "Telephony: Consider EVDO ecio zero value as valid."

This reverts commit 3dbc6cae3ecc6356be8f046a1ed0194613570da5.
Custom carrier laberl (1/2)