Change PDP_FAIL_SIGNAL_LOST to be retryable.

We've changed this in the framework:

 https://googleplex-android-review.git.corp.google.com/#/c/366996/

So this updates ril.h to match.

Bug: 10954174, 10804691
Change-Id: I820d44e74251fd4fc375551474341572e9020aee
diff --git a/include/telephony/ril.h b/include/telephony/ril.h
index 2957441..766d5da 100644
--- a/include/telephony/ril.h
+++ b/include/telephony/ril.h
@@ -399,7 +399,7 @@
     PDP_FAIL_DATA_REGISTRATION_FAIL = -2,
 
    /* reasons for data call drop - network/modem disconnect */
-    PDP_FAIL_SIGNAL_LOST = -3,            /* no retry */
+    PDP_FAIL_SIGNAL_LOST = -3,
     PDP_FAIL_PREF_RADIO_TECH_CHANGED = -4,/* preferred technology has changed, should retry
                                              with parameters appropriate for new technology */
     PDP_FAIL_RADIO_POWER_OFF = -5,        /* data call was disconnected because radio was resetting,