soc: mediatek: svs: Fix memory leak in svs_enable_debug_write()

In the Linux kernel, the following vulnerability has been resolved: soc: mediatek: svs: Fix memory leak in svs_enable_debug_write() In svs_enable_debug_write(), the buf allocated by memdup_user_nul() is leaked if kstrtoint() fails. Fix this by using __free(kfree) to automatically free buf, eliminating the need for explicit kfree() calls and preventing leaks. [Angelo: Added missing cleanup.h inclusion]