Merge branch 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull x86 interrupt updates from Thomas Gleixner:
 "A small set of changes to simplify and improve the interrupt handling
  in do_IRQ() by moving the common case into common code and thereby
  cleaning it up"

* 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/irq: Check for VECTOR_UNUSED directly
  x86/irq: Move IS_ERR_OR_NULL() check into common do_IRQ() code
  x86/irq: Improve definition of VECTOR_SHUTDOWN et al