selftests: kvm: Raise the default timeout to 120 seconds

With the updated maximum number of user memslots (32)
set_memory_region_test sometimes takes longer than the default 45 seconds
to finish. Raise the value to an arbitrary 120 seconds.

Signed-off-by: Vitaly Kuznetsov <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Paolo Bonzini <[e-mail]>

tools/testing/selftests/kvm/settings

···
+timeout=120