lcs: Add missing destroy_timer_on_stack()

Otherwise we leak a tracking object when DEBUG_OBJECTS is enabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>