PPIs are affine by nature, so the interrupt-affinity property is not
used and therefore we shouldn't print a warning in its absence.
Reported-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>