Telephony: SMS over IMS

Add RIL_REQUEST_IMS_REGISTRATION_STATE, RIL_REQUEST_IMS_SEND_SMS, and
RIL_UNSOL_RESPONSE_IMS_NETWORK_STATE_CHANGED.  Add FORMAT_UNKNOWN to
SmsConstants.

Change-Id: I87ca9841b4ace931c55e2d379fe6d7589b2dc8a5
(cherry picked from commit 876c2cdbcfb2650c30da158ecccf2d1eeaa7a916)
(cherry picked from commit f0cf40d0aa80b01607c394cc613a9ca708e4affe)
(cherry picked from commit 8ed4a4e1f2a0b9e86ddae0f5813bce41c6e312f8)