Merge branch 'irq/for-xen' into irq/core

irq/for-xen contains new functionality to avoid Xen private irq
hackery. That branch has a single irq commit and is pulled by Xen to
base their new features on.

Merge it into irq/core as other patches modify the same code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>