do not truncate irq number for icom adapter

irq values are u32, not u8. Large irq numbers will be truncated,
free_irq may free a different irq.

Remove incorrectly sized struct member and use the one from pci_dev.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>