KVM: arm64: Introduce kvm_counter_compute_delta() helper

mainline inclusion
from mainline-v5.19-rc1
commit daf85a5f
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6YAMV
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=daf85a5f6be33788e18ff3efad1d7c3ad66a8cb3



-------------------------------

Refactor kvm_timer_compute_delta() and extract a helper that
compute the delta (in ns) between a given timer and an arbitrary
value.

No functional change expected.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220419182755.601427-5-maz@kernel.org


Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>