wifi: iwlwifi: fw: fix memory leak in debugfs

wifi: iwlwifi: fw: fix memory leak in debugfs

Fix a memory leak that occurs when reading the fw_info
file all the way, since we return NULL indicating no
more data, but don't free the status tracking object.

Fixes: 36dfe9ac6e8b ("iwlwifi: dump api version in yaml format")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230418122405.239e501b3b8d.I4268f87809ef91209cbcd748eee0863195e70fa2@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>