ARM: KVM: extend WFI tracepoint to differentiate between wfi and wfe

Currently the trace printk talks about "wfi" only, though the trace
point triggers both on wfi and wfe traps.
Add a parameter to differentiate between the two.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Wei Huang <wei@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>