x86: Implement arch_setup/teardown_hwirq()

This is just a cleanup to get rid of the create/destroy_irq variants
which were designed in hell.

The long term solution for x86 is to switch over to irq domains and
cleanup the whole vector allocation mess.

The generic irq_alloc_hwirqs() interface deliberately prevents
multi-MSI vector allocation to further enforce the irq domain
conversion (aside of the desire to support ioapic hotplug).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20140507154334.482904047@linutronix.de


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