v2: Change device parameter permissions to 0400

Cc: Luca Coelho <luciano.coelho@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231024124109.384973-22-jouni.hogander@intel.com