genirq: Move IRQ_ONESHOT to core

No users outside of core.

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

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

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

diff --cc kernel/irq/internals.h
Simple merge

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