KVM: selftests: Fixup config fragment for access_tracking_perf_test

access_tracking_perf_test requires CONFIG_IDLE_PAGE_TRACKING. However
this is missing from the config fragment, so add it in so that this test
is no longer skipped.

Signed-off-by: Ryan Roberts <[e-mail]>
Reviewed-by: Sean Christopherson <[e-mail]>
Reviewed-by: Oliver Upton <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

tools/testing/selftests/kvm/config

···
 CONFIG_KVM_INTEL=y
 CONFIG_KVM_AMD=y
 CONFIG_USERFAULTFD=y
+CONFIG_IDLE_PAGE_TRACKING=y