Adding missing NI_TYPE for emergency SUPL

Bug: 37409476
Test: Builds, and on Pixel, basic GPS & XTRA tests pass.
Partners & Pixel team running the SUPL emergency tests.

Change-Id: I6b23608e82dc1682d61a516ab5045d3b78b53cae
diff --git a/gnss/1.0/IGnssNiCallback.hal b/gnss/1.0/IGnssNiCallback.hal
index 163ba25..3e3071a 100644
--- a/gnss/1.0/IGnssNiCallback.hal
+++ b/gnss/1.0/IGnssNiCallback.hal
@@ -25,7 +25,8 @@
     enum GnssNiType : uint8_t {
         VOICE           = 1,
         UMTS_SUPL       = 2,
-        UMTS_CTRL_PLANE = 3
+        UMTS_CTRL_PLANE = 3,
+        EMERGENCY_SUPL  = 4
     };
 
     /**