Fixed the incorrect operator name displayed when roaming.

The operator name was incorrectly overwritten when roaming
on partner's LTE network. In that case, ERI roaming indicator
is off, NID/SID is zero (because LTE does not support ERI/NID/SID).

The original requirement for using the name from CSIM EF_SPN
is for CDMA only (b/5008969), therefore we need to make sure the
logic is not applied in the LTE case.

bug: 22951507
Change-Id: I3595228e1a637f4bfd05e34cf9a702bb0e1bba59