Notify user regarding invalid number during MO call.

When user dials an invalid number, network returns a failure
as "unobtainable number" (See the Table 10.5.123/3GPP TS 24.008 for
the possible failure causes). Changes done to display message to
indicate user that an invalid number has been dialed.

Change-Id: Ibe191991ee6f24dd683dca47f6af54e400ef17df
diff --git a/include/telephony/ril.h b/include/telephony/ril.h
index 185f3c0..487830d 100644
--- a/include/telephony/ril.h
+++ b/include/telephony/ril.h
@@ -256,6 +256,7 @@
 
 /* See RIL_REQUEST_LAST_CALL_FAIL_CAUSE */
 typedef enum {
+    CALL_FAIL_UNOBTAINABLE_NUMBER = 1,
     CALL_FAIL_NORMAL = 16,
     CALL_FAIL_BUSY = 17,
     CALL_FAIL_CONGESTION = 34,