arm: iop13xx: Use sparse irqs for MSI

No need for a private allocator. The core code handles it
already.

Allocate the non MSI irqs right at boot time via machine_desc->nr_irqs
and let the sparse core handle the MSI space.

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: Dan Williams <dan.j.williams@intel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20140507154333.809210026@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>