legal info: cleanup utility functions

The legal-info utility functions where defined using two ways
util-foo = command-foo
and
define util-bar # parameter description
	command-bar
endef

This commit changes these functions to use the second form for clarity and
additionally adds parameter descriptions on all functions.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Acked-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>