KVM: arm/arm64: vgic: fix possible spectre-v1 in vgic_get_irq()

It's possible for userspace to control intid. Sanitize intid when using
it as an array index.

At the same time, sort the includes when adding <linux/nospec.h>.

Found by smatch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Will Deacon <will.deacon@arm.com>