KVM: arm64: Add unified helper for reprogramming counters by mask

KVM: arm64: Add unified helper for reprogramming counters by mask

Having separate helpers for enabling/disabling counters provides the
wrong abstraction, as the state of each counter needs to be evaluated
independently and, in some cases, use a different global enable bit.

Collapse the enable/disable accessors into a single, common helper that
reconfigures every counter set in @mask, leaving the complexity of
determining if an event is actually enabled in
kvm_pmu_counter_is_enabled().

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241217175513.3658056-1-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>