MIPS: KVM: Combine entry trace events into class

Combine the kvm_enter, kvm_reenter and kvm_out trace events into a
single kvm_transition event class to reduce duplication and bloat.

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Fixes: 93258604

 ("MIPS: KVM: Add guest mode switch trace events")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>