perf annotate: Re-add annotate_warned functionality

Setting annotate_warned to true on errors was removed in
commit ee51d851 ("perf annotate: Introduce strerror for handling
symbol__disassemble() errors") which means when 'perf annotate
--skip-missing' is used warnings are shown multiple times for the same
DSO.

Setting this again restores the original behavior of only one warning
each.

Signed-off-by: James Clark <james.clark@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lore.kernel.org/lkml/20210729155805.2830-3-james.clark@arm.com


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