mei: me: add kdoc for mei_me_fw_type_nm()

Add kdoc for mei_me_fw_type_nm() function.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20200619165121.2145330-4-tomas.winkler@intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>