We have 3 identical copies of the ioapic domain ops for acpi, mpparse,
and sfi. Have a global one in the io_apic code and be done with it.

To avoid include hell in io_apic.h, create a private irqdomain header
and include the generic irqdomain header from there.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: sfi-devel@simplefirmware.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1428978610-28986-32-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>