KVM: arm64: vgic-v3: Release reserved slot outside of lpi_xa's lock

KVM: arm64: vgic-v3: Release reserved slot outside of lpi_xa's lock

xa_release() expects to be called outside of the xa_lock. Fix
vgic_add_lpi() to drop the lock before calling and restructure to get
rid of the goto label.

Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Closes: https://lore.kernel.org/kvmarm/d0853e82-7d95-5025-7abf-c6f1e0cdf7b5@huawei.com/
Fixes: 481c9ee846d2 ("KVM: arm64: vgic-its: Get rid of the lpi_list_lock")
Signed-off-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20251107184847.1784820-3-oupton@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>