irqchip/gic: Return IRQ_SET_MASK_OK_DONE in the set_affinity method

Moving an SPI around doesn't require any extra work from the rest
of the stack, and specially not for MSI-generated SPIs.

It is then worth returning IRQ_SET_MASK_OK_DONE instead of
IRQ_SET_MASK_OK, and simplify the other irqchips that rely on
this behaviour (GICv2m and Marvell's ODMI controller).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1455894029-17270-1-git-send-email-marc.zyngier@arm.com


Signed-off-by: Jason Cooper <jason@lakedaemon.net>