Improve carrierconfig to support multisim in GsmCdmaPhone

Use subId to check below keys of carrierconfig in GsmCdmaPhone

KEY_DEFAULT_VM_NUMBER_STRING
KEY_CONFIG_TELEPHONY_USE_OWN_NUMBER_FOR_VOICEMAIL_BOOL
KEY_SUPPORT_3GPP_CALL_FORWARDING_WHILE_ROAMING_BOOL

Test: Manual
      1.Prepare multisim device.
      2.Insert two simcards which have different key in vendor.xml
      3.Check voice-mail number.

Change-Id: I7a05c99d25228f5b6c691e1bd57b2eb0e6f007a6