kmsdrm: restrict KMSDRM_ReleaseVT/KMSDRM_AcquireVT to SDL_INPUT_LINUXEV

src/video/kmsdrm/SDL_kmsdrmvideo.c

@@ -1222,6 +1222,7 @@ cleanup:
     return ret;
 }
 
+#ifdef SDL_INPUT_LINUXEV
 static void KMSDRM_ReleaseVT(void *userdata)
 {
     SDL_VideoDevice *_this = (SDL_VideoDevice *)userdata;
@@ -1251,6 +1252,7 @@ static void KMSDRM_AcquireVT(void *userdata)
         }
     }
 }
+#endif /* defined SDL_INPUT_LINUXEV */
 
 int KMSDRM_VideoInit(SDL_VideoDevice *_this)
 {