kconfig: Fix some formatting nits

Same deal as in commit bd6e0441 ("kconfig: Clean up header comments
and make them consistent") and commit 1f38ea77 ("kconfig: Clean up
'config  FOO' (two spaces) definitions"), for some newly-introduced
stuff.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>