base: Export platform_msi_domain_[alloc,free]_irqs

The new function platform_msi_domain_{alloc,free}_irqs are meant to be
used in platform drivers, which can be built as modules. Therefore, it
makes sense to export them to be used from kernel modules.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Link: http://lkml.kernel.org/r/1453816347-32720-4-git-send-email-marc.zyngier@arm.com


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