perf lock: Fix a memory leak on an error path

perf lock: Fix a memory leak on an error path

if a strdup-ed string is NULL,the allocated memory needs freeing.

Signed-off-by: zhaimingbing <zhaimingbing@cmss.chinamobile.com>
Acked-by: Ingo Molnar <mingo@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Dong <lidong@vivo.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20231124092657.10392-1-zhaimingbing@cmss.chinamobile.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>