irqchip/gic-v4: Fix ordering between vmapp and vpe locks

The recently established lock ordering mandates that the per-VM
vmapp_lock is acquired before taking the per-VPE lock.

As it turns out, its_vpe_set_affinity() takes the VPE lock, and
then calls into its_send_vmovp(), which itself takes the vmapp
lock. Obviously, this is a lock order violation.

As its_send_vmovp() is only called from its_vpe_set_affinity(),
hoist the vmapp locking from the former into the latter, restoring
the expected order.

Fixes: f0eb154c ("irqchip/gic-v4: Substitute vmovp_lock for a per-VM lock")
Reported-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240818171625.3030584-1-maz@kernel.org