x86, irq: Move irq_remapped() check into free_remapped_irq

The function is called unconditionally now in IO-APIC code
removing another irq_remapped() check from x86 core code.

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>