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>
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 893503f..82f95f4 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -4,6 +4,7 @@
 config PCI_MSI
 	bool "Message Signaled Interrupts (MSI and MSI-X)"
 	depends on PCI
+	select GENERIC_MSI_IRQ
 	help
 	   This allows device drivers to enable MSI (Message Signaled
 	   Interrupts).  Message Signaled Interrupts enable a device to