PhoneProxy: Update IccCardProxy only when cdma voice tech changes.

This fixes MMS, at least on toro: http://review.cyanogenmod.org/#/c/49346/	

Update IccCardProxy only when the device is reporting new cdma voice tech.
	Fixes scenario where device reports UNSOL_VOICE_TECH_CHANGE to UMTS, but remains
        as a CdmaLtePhone.

Change-Id: I81bd5d3c6cf553c0a60ad3d4f1f581d3500f446c