perf annotate: Add support to identify memory instructions of opcode 31 in powerpc

There are memory instructions in powerpc with opcode as 31.
Example: "ldx RT,RA,RB" , Its X form is as below:

  ______________________________________
  | 31 |  RT  |  RA |  RB |   21     |/|
  --------------------------------------
  0    6     11    16    21         30 31

The opcode for "ldx" is 31. There are other instructions also with
opcode 31 which are memory insn like ldux, stbx, lwzx, lhaux
But all instructions with opcode 31 are not memory. Example is add
instruction: "add RT,RA,RB"

The value in bit 21-30 [ 21 for ldx ] is different for these
instructions. Patch uses this value to assign instruction ops for these
cases. The naming convention and value to identify these are picked from
defines in "arch/powerpc/include/asm/ppc-opcode.h"

Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Kajol Jain <kjain@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Akanksha J N <akanksha@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Disha Goel <disgoel@linux.vnet.ibm.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Link: https://lore.kernel.org/lkml/20240718084358.72242-9-atrajeev@linux.vnet.ibm.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>