KVM: arm64: selftests: Fix help text for arch_timer_edge_cases

Fix the help text for arch_timer_edge_cases to show the correct
option for setting the wait time.

Signed-off-by: Sebastian Ott <sebott@redhat.com>
Link: https://lore.kernel.org/r/20250605103613.14544-2-sebott@redhat.com


Signed-off-by: Marc Zyngier <maz@kernel.org>