bfin: Final irq cleanup

Use the trigger type in irq_data and check level type instead of
looking at desc->handle_irq.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: uclinux-dist-devel@blackfin.uclinux.org