[NAN] Renamed listeners to callback per API guidelines

The interfaces had multiple functions and are hence callback
and not a listener.

Note: purely a rename operation.

(cherry-pick of 0d0f0c7faf530a0fa5595dd539c3f56afeb6603a,
 Change-Id: Ib12711f56a64052455843859125d72268c465fc0)

Bug: 27122760
Change-Id: Ie1905a5d907e5b09d449af52814b1aacb6426477
(cherry picked from commit 4e1af1b80735f5d61f089432a63a23937c994546)
diff --git a/Android.mk b/Android.mk
index 1750c7c..69e57b6 100644
--- a/Android.mk
+++ b/Android.mk
@@ -449,9 +449,9 @@
 	telephony/java/com/android/internal/telephony/ITelephonyRegistry.aidl \
 	telephony/java/com/android/internal/telephony/IWapPushManager.aidl \
 	wifi/java/android/net/wifi/IWifiManager.aidl \
-	wifi/java/android/net/wifi/nan/IWifiNanEventListener.aidl \
+	wifi/java/android/net/wifi/nan/IWifiNanEventCallback.aidl \
 	wifi/java/android/net/wifi/nan/IWifiNanManager.aidl \
-	wifi/java/android/net/wifi/nan/IWifiNanSessionListener.aidl \
+	wifi/java/android/net/wifi/nan/IWifiNanSessionCallback.aidl \
 	wifi/java/android/net/wifi/p2p/IWifiP2pManager.aidl \
 	wifi/java/android/net/wifi/IWifiScanner.aidl \
 	wifi/java/android/net/wifi/IRttManager.aidl \