arm: Move chained_irq_(enter|exit) to a generic file

arm: Move chained_irq_(enter|exit) to a generic file

These functions have been introduced by commit 10a8c383 (irq: introduce
entry and exit functions for chained handlers) in asm/mach/irq.h. This
patch moves them to linux/irqchip/chained_irq.h so that generic irqchip
drivers do not rely on architecture specific header files.

Signed-off-by: Catalin Marinas <[email protected]>
Tested-by: Marc Zyngier <[email protected]>
Cc: Russell King <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Rob Herring <[email protected]>