arm64: irq: Notify affinity change when migrating IRQs during hotplug

Hotplug causes IRQs affine to a core that is being taken down to migrate
to an online core. This is done by directly calling the irq_set_affinity
associated with the irq_chip structure. Instead using the
irq_set_affinity() api lets the notifications bubble through.

Change-Id: Ifedd6726dedffd751aee7da2e88dbb802dfa535e
Signed-off-by: Praveen Chidambaram <pchidamb@codeaurora.org>