irqchip: mips-gic: Use cpumask_first_and() in gic_set_affinity()

Currently in gic_set_affinity() we calculate a temporary cpumask holding
the intersection of the provided cpumask & the CPUs that are online,
then we call cpumask_first twice on it to find the first such CPU. Since
we don't need the temporary cpumask for anything else & we only care
about the first CPU that's both online & in the provided cpumask, we can
instead use cpumask_first_and to find that CPU & drop the temporary
mask.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17110/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>