perf annotate: Don't pipe objdump output through 'grep' command

perf annotate: Don't pipe objdump output through 'grep' command

Simplify the objdump command by not piping the output of objdump through
grep. Instead, drop lines that match the grep pattern during the reading
loop.

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: clang-built-linux@googlegroups.com
Link: http://lore.kernel.org/lkml/20191010183649.23768-4-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>