perf list: Escape '\r' in JSON output

perf list: Escape '\r' in JSON output

Events like for sapphirerapids have '\r' in the uncore descriptions. The
non-escaped versions of this fail JSON validation the the 'perf list'
test.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240410222353.1722840-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>