perf powerpc: Refactor the code definition of perf reg extended mask in tools side header file

PERF_REG_PMU_MASK_300 and PERF_REG_PMU_MASK_31 defines the mask value
for extended registers. Current definition of these mask values uses hex
constant and does not use registers by name, making it less readable.
Patch refactor the macro values in perf tools side header file by or'ing
together the actual register value constants.

Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20211018114948.16830-2-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>