Clarify new setRadioPower documentation

There were some questions on how the new IRadio 1.5 setRadioPower
command should be implemented based on vendor feedback. This CL
clarifies this behavior.

Test: manual
Bug: 143683647
Change-Id: If08741f0ea156a5c2656a47e46f7e1f98bf54ec4
Merged-In: If08741f0ea156a5c2656a47e46f7e1f98bf54ec4
diff --git a/radio/1.5/IRadio.hal b/radio/1.5/IRadio.hal
index 6ebbcb4..956f9bd 100644
--- a/radio/1.5/IRadio.hal
+++ b/radio/1.5/IRadio.hal
@@ -238,7 +238,8 @@
      * 1) Emergency call is completed; or
      * 2) Another setRadioPower_1_5 is issued with forEmergencyCall being false or
      * preferredForEmergencyCall being false; or
-     * 3) Timeout after a long period of time.
+     * 3) Timeout after 30 seconds if dial or emergencyDial is not called.
+     * Once one of these conditions is reached, the modem should move into normal operation.
      *
      * @param serial Serial number of request.
      * @param powerOn To turn on radio -> on = true, to turn off radio -> on = false.