perf disasm: Fix capstone memory leak

perf disasm: Fix capstone memory leak

The insn argument passed to cs_disasm needs freeing. To support
accurately having count, add an additional free_count variable.

Fixes: c5d60de1813a ("perf annotate: Add support to use libcapstone in powerpc")
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20241016235622.52166-2-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>