android: Fix scancode for AKEYCODE_CHANNEL_DOWN

(cherry picked from commit f0bda7b)

Author: cgutman

src/video/android/SDL_androidkeyboard.c

@@ -238,7 +238,7 @@ static SDL_Scancode Android_Keycodes[] = {
     SDL_SCANCODE_UNKNOWN,          // AKEYCODE_VOLUME_MUTE
     SDL_SCANCODE_UNKNOWN,          // AKEYCODE_INFO
     SDL_SCANCODE_CHANNEL_INCREMENT, // AKEYCODE_CHANNEL_UP
-    SDL_SCANCODE_CHANNEL_INCREMENT, // AKEYCODE_CHANNEL_DOWN
+    SDL_SCANCODE_CHANNEL_DECREMENT, // AKEYCODE_CHANNEL_DOWN
     SDL_SCANCODE_UNKNOWN,          // AKEYCODE_ZOOM_IN
     SDL_SCANCODE_UNKNOWN,          // AKEYCODE_ZOOM_OUT
     SDL_SCANCODE_UNKNOWN,          // AKEYCODE_TV