perf tests dlfilter: Free desc and long_desc in check_filter_desc

perf tests dlfilter: Free desc and long_desc in check_filter_desc

In dlfilter-test.c, check_filter_desc() calls get_filter_desc() which
allocates 'desc' and 'long_desc'.  However, these variables are never
deallocated.

This patch adds the missing free() calls.

Fixes: 9f9c9a8de2d5e96c ("perf tests: Add dlfilter test")
Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.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>
Link: http://lore.kernel.org/lkml/20210820113132.724034-1-rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>