wifi: iwlwifi: mvm: add DSM_FUNC_ENABLE_6E value to debugfs

In order to simplify checking that this value was set up
correctly, add it to debugfs.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230413213309.c9a787710e1e.If509b2e510e22d62f3eefb2c54ff1645e331dc23@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>