irq: use GFP_KERNEL for action allocation in request_irq()

request_irq() calls into proc code via __setup_irq() which is not safe
in an atomic context, so request_irq() can itself use the more
reliable GFP_KERNEL allocation for the action descriptor.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>