perf intel-pt-decoder: Avoid checking code drift on busibox's diff

perf intel-pt-decoder: Avoid checking code drift on busibox's diff

That doesn't have -I to match lines.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-7nz9hnbk7a9p91ou927ye5yh@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>