kconfigfunctions: Disambiguate reference to DTS generated database

Documentation for kconfigfunctions, mentions they look up elements
in "the DTS generated "conf" style database". This indication
could be cryptic for new zephyr users. Adding the exact name and
path of the file for disambiguation.

Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
2 files changed