ARM: KVM: Simplify tracepoint text

The tracepoint for kvm_guest_fault was extremely long, make it a
slightly bit shorter.

Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>