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 <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-list.c

···
 					case '\n':
 						strbuf_addstr(buf, "\\n");
 						break;
+					case '\r':
+						strbuf_addstr(buf, "\\r");
+						break;
 					case '\\':
 						fallthrough;
 					case '\"':