Add RIL_UNSOL_MODEM_RESTART message

RIL_UNSOL_MODEM_RESTART will be sent by vendor RILs when it detects
a modem restart along with the reason for restart which could be a
crash signature if the modem restarted due to a crash or a some
other string such as a user-initiated restart or AT command
initiated restart.

Change-Id: Idf08e20a49e82d40f6aa0854d23384c35c2efc3a

telephony/java/com/android/internal/telephony/RILConstants.java

@@ -462,4 +462,5 @@ cat include/telephony/ril.h | \
     int RIL_UNSOL_STK_CC_ALPHA_NOTIFY = 1044;
     int RIL_UNSOL_LCEDATA_RECV = 1045;
     int RIL_UNSOL_PCO_DATA = 1046;
+    int RIL_UNSOL_MODEM_RESTART = 1047;
 }