video: sh7760fb: fix to pass correct device identity to free_irq()

free_irq() expects the same device identity that was passed to
corresponding request_irq(), otherwise the IRQ is not freed.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>