Input: twl4030-pwrbutton - fix a leak of the IRQ during init failure

In twl4030_pwrbutton_probe error path, free_irq() was using NULL rather than
the driver data as the data pointer so free_irq() wouldn't have matched.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>