wifi: Fixing Nits

Changes in the CL to fix bugs found while integrating
with framework:
1. Added IWifiApIface.setCountryCode()
Bug: 34682168
2. Fixed documentation nits in .hal files.
Bug: 34468218
3. Changed roaming state enum values.
Bug: 34715231
4. Added log for EBUSY in legacyErrorToString()
Bug: 34715469
5. Remove "-Wno-unused parameter" from Android.mk
Bug: 34611289
6. Remove the erroneous |onFailure| callback invocation in wifi.cpp.
7. Add null terminations to strings passed to legacy HAL API's
8. Remove unused |IWifiStaIface.stopDebugPacketFateMonitoring|.

Test: Compiles
Change-Id: If3a3e2f360a378c59dc56b8bbe3a0c6d400b3bd8
diff --git a/wifi/1.0/default/wifi_status_util.cpp b/wifi/1.0/default/wifi_status_util.cpp
index 518032f..c2d0758 100644
--- a/wifi/1.0/default/wifi_status_util.cpp
+++ b/wifi/1.0/default/wifi_status_util.cpp
@@ -42,8 +42,9 @@
       return "TOO_MANY_REQUESTS";
     case legacy_hal::WIFI_ERROR_OUT_OF_MEMORY:
       return "OUT_OF_MEMORY";
+    case legacy_hal::WIFI_ERROR_BUSY:
+      return "BUSY";
     case legacy_hal::WIFI_ERROR_UNKNOWN:
-    default:
       return "UNKNOWN";
   }
 }
@@ -90,7 +91,6 @@
       return createWifiStatus(WifiStatusCode::SUCCESS, desc);
 
     case legacy_hal::WIFI_ERROR_UNKNOWN:
-    default:
       return createWifiStatus(WifiStatusCode::ERROR_UNKNOWN, "unknown");
   }
 }