Merge "Document emergency case for setAllowedNetworkTypeBitmap" am: e9fb347e0b am: fd6c4f5f5d

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/1531900

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I236a749c4626e2672a82621925870d8ecc78ce0c
diff --git a/radio/1.6/IRadio.hal b/radio/1.6/IRadio.hal
index 4e9dcdb..df28940 100644
--- a/radio/1.6/IRadio.hal
+++ b/radio/1.6/IRadio.hal
@@ -330,6 +330,9 @@
      * Instruct the radio to *only* accept the types of network provided. This
      * is stronger than setPreferredNetworkType which is a suggestion.
      *
+     * In case of an emergency call, the modem is authorized to bypass this
+     * restriction.
+     *
      * @param serial Serial number of request.
      * @param networkTypeBitmap a 32-bit bearer bitmap of RadioAccessFamily
      *