PCI/MSI: Move cached entry functions to irq core

Required to support non PCI based MSI.

[ tglx: Extracted from Jiangs patch series ]

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
(cherry picked from commit 38b6a1cf3e4df0a3267c01fab699ab65d58690f4)
Signed-off-by: Alex Shi <alex.shi@linaro.org>