selftests: kvm/x86: Add the helper function create_pmu_event_filter

Add a helper function that creates a pmu event filter given an event
list.  Currently, a pmu event filter can only be created with the same
hard coded event list.  Add a way to create one given a different event
list.

Also, rename make_pmu_event_filter to alloc_pmu_event_filter to clarify
it's purpose given the introduction of create_pmu_event_filter.

No functional changes intended.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <20220517051238.2566934-2-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>