perf top: Initialize perf_env->cpuid, needed by the per arch annotation init routine

perf top: Initialize perf_env->cpuid, needed by the per arch annotation init routine

Just read it so that later on the per arch init routine can use it,
e.g. x86__annotate_init().

When using a perf.data file this is obtained from a header that was put
there by 'perf record', and then it may be for another machine, another
arch.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-4t4n3o8l8s0tc2b1pq53hyr4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>