genirq: threaded irq handlers review fixups

Delta patch to address the review comments.

      - Implement warning when IRQ_WAKE_THREAD is requested and no
        thread handler installed
      - coding style fixes

Pointed-out-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --cc include/linux/interrupt.h
Simple merge

diff --cc kernel/irq/handle.c
Simple merge

diff --cc kernel/irq/manage.c
Simple merge