wifi: rename mode 'ON' to 'VOICE'.

To improve clarity and accommodate future functionalities,
we should rename the existing 'ON' mode to 'VOICE'.
This change establishes 'VOICE' as the fundamental mode for VOIP operations.
Additionally, it paves the way for adding future modes, such as 'VOICE_VIDEO',
as the system evolves.

Bug: 295885471
Test: TH

Change-Id: Ie3b54f02cf3c73b5a9c2a805ec36703dfd541666
diff --git a/wifi/aidl/default/wifi_chip.cpp b/wifi/aidl/default/wifi_chip.cpp
index 2db3b4a..9b9c565 100644
--- a/wifi/aidl/default/wifi_chip.cpp
+++ b/wifi/aidl/default/wifi_chip.cpp
@@ -1924,7 +1924,7 @@
     wifi_voip_mode mode;
     switch (in_mode) {
         case WifiChip::VoipMode::VOICE:
-            mode = wifi_voip_mode::WIFI_VOIP_MODE_ON;
+            mode = wifi_voip_mode::WIFI_VOIP_MODE_VOICE;
             break;
         case WifiChip::VoipMode::OFF:
             mode = wifi_voip_mode::WIFI_VOIP_MODE_OFF;