sdl: set app name

Ryujinx was not hinting application name, so on some platforms (e.g.
Linux) volume control shows Ryujinx as 'SDL Application'. This can cause
confusion.

This commit fixes name in volume control applets on some platforms.

see: https://wiki.libsdl.org/SDL2/SDL_HINT_APP_NAME

src/Ryujinx.SDL2.Common/SDL2Driver.cs

@@ -53,6 +53,7 @@ namespace Ryujinx.SDL2.Common
                     return;
                 }
 
+                SDL_SetHint(SDL_HINT_APP_NAME, "Ryujinx");
                 SDL_SetHint(SDL_HINT_JOYSTICK_HIDAPI_PS4_RUMBLE, "1");
                 SDL_SetHint(SDL_HINT_JOYSTICK_HIDAPI_PS5_RUMBLE, "1");
                 SDL_SetHint(SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS, "1");