kvm: powerpc: book3s: pr: move PR related tracepoints to a separate header

This patch moves PR related tracepoints to a separate header. This
enables in converting PR to a kernel module which will be done in
later patches

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>