perf disasm: Rework the string arch__is to use the ELF machine

perf disasm: Rework the string arch__is to use the ELF machine

Add new arch__is_x86 and arch__is_powerpc functions that avoid string
comparisons and use the ELF machine.

Remove arch__is() that is no longer used.

Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Aditya Bodkhe <aditya.b1@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Julia Lawall <Julia.Lawall@inria.fr>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Krzysztof Łopatowski <krzysztof.m.lopatowski@gmail.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergei Trofimovich <slyich@gmail.com>
Cc: Shimin Guo <shimin.guo@skydio.com>
Cc: Suchit Karunakaran <suchitkarunakaran@gmail.com>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Tianyou Li <tianyou.li@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zecheng Li <zecheng@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>