iommu/vt-d: Mark function eoi_ioapic_pin_remapped() as static in irq_remapping.c

Mark function eoi_ioapic_pin_remapped() as static in irq_remapping.c
because it is not used outside this file.

This eliminates the following warning in
irq_remapping.c:drivers/iommu/irq_remapping.c:153:6: warning: no
previous prototype for ‘eoi_ioapic_pin_remapped’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Joerg Roedel <joro@8bytes.org>