perf powerpc: Update global/local variants for p_stage_cyc

Update the arch_support_sort_key() function in powerpc to enable
presenting local and global variants of sort key 'p_stage_cyc'.

Update the "se_header" strings for these in arch_perf_header_entry()
along with instruction latency.

Reported-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20211203022038.48240-2-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>