perf symbols: Fix type error when reading a build-id

This was benign, but wrong. The build-id should live in a char[], not a char*[]

Signed-off-by: Dima Kogan <dima@secretsauce.net>
Link: http://lkml.kernel.org/r/87si6pfwz4.fsf@secretsauce.net


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