genirq: Replace dynamic_irq_init/cleanup

Create a new interface and confine it with a config switch which makes
clear that this is just legacy support and not to be used for new code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140507154340.574437049@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --cc include/linux/irq.h
Simple merge

diff --cc kernel/irq/Kconfig
Simple merge

diff --cc kernel/irq/irqdesc.c
Simple merge