thermal/drivers/mediatek/lvts: Remove unused lvts_debugfs_exit

When debugfs is disabled, the function has no reference any more:

drivers/thermal/mediatek/lvts_thermal.c:266:13: error: 'lvts_debugfs_exit' defined but not used [-Werror=unused-function]
  266 | static void lvts_debugfs_exit(struct lvts_domain *lvts_td) { }
      |             ^~~~~~~~~~~~~~~~~

Fixes: ef280c1 ("thermal/drivers/mediatek/lvts: Fix debugfs unregister on failure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20250505052502.1812867-1-arnd@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Author: arndb

drivers/thermal/mediatek/lvts_thermal.c

@@ -263,8 +263,6 @@ static inline int lvts_debugfs_init(struct device *dev,
 	return 0;
 }
 
-static void lvts_debugfs_exit(struct lvts_domain *lvts_td) { }
-
 #endif
 
 static int lvts_raw_to_temp(u32 raw_temp, int temp_factor)