powerpc/perf: Fix the threshold event selection for memory events in power10

Memory events (mem-loads and mem-stores) currently use the threshold
event selection as issue to finish. Power10 supports issue to complete
as part of thresholding which is more appropriate for mem-loads and
mem-stores. Hence fix the event code for memory events to use issue
to complete.

Fixes: a64e697c ("powerpc/perf: power10 Performance Monitoring support")
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1614840015-1535-1-git-send-email-atrajeev@linux.vnet.ibm.com