wifi: Improve documentation of hidl APIs.

Added changes as per ANAPIC review to improve
documentation of few hidl APIs.

Bug: 148617258
Test: Not tested as there is no code change.
Change-Id: I3f91c6b8aad3f34807534a3fbc3cf5a3c3233cd7
diff --git a/wifi/supplicant/1.3/ISupplicantStaIfaceCallback.hal b/wifi/supplicant/1.3/ISupplicantStaIfaceCallback.hal
index 6828dcd..c5da29c 100644
--- a/wifi/supplicant/1.3/ISupplicantStaIfaceCallback.hal
+++ b/wifi/supplicant/1.3/ISupplicantStaIfaceCallback.hal
@@ -147,7 +147,7 @@
     };
 
     /**
-     * Indicates PMK cache added event.
+     * Indicates pairwise master key (PMK) cache added event.
      *
      * @param expirationTimeInSec expiration time in seconds
      * @param serializedEntry is serialized PMK cache entry, the content is
@@ -192,6 +192,9 @@
 
     /**
      * Indicates an EAP authentication failure.
+     * @param errorCode Error code for EAP authentication failure.
+     *        Either standard error code (enum EapErrorCode) or
+     *        private error code defined by network provider.
      */
     oneway onEapFailure_1_3(uint32_t errorCode);