x86, io-apic: Move CONFIG_IRQ_REMAP code out of x86 core

Move all the code to either to the header file
asm/irq_remapping.h or to drivers/iommu/.

Signed-off-by: Joerg Roedel <joro@8bytes.org>
Acked-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>