gpio: timbgpio: Fix up irq_data conversion breakage.

Commit a1f5f22a ("gpio: timbgpio:
irq_data conversion") was slightly too enthusiastic in converting
timbgpio_irq() over to take an irq_data * argument instead of an
unsigned int irq argument, as it is a flow handler, which still take
IRQ numbers for now.  (And on top of that, it was using the wrong
accessors.)

This fixes it up, and seems to build without warnings.

Signed-off-by: Lennert Buytenhek <buytenh@secretlab.ca>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Richard Röjfors <richard.rojfors@mocean-labs.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>