[KMS/DRM] Replace indent tabs with spaces, as intended.

src/video/kmsdrm/SDL_kmsdrmmouse.c

@@ -456,6 +456,7 @@ KMSDRM_WarpMouseGlobal(int x, int y)
         } else {
             return SDL_SetError("Cursor not initialized properly.");
         }
+
     } else {
         return SDL_SetError("No mouse or current cursor.");
     }