Symbols without prompt cannot be configured from application
configuration file.
warning: BT_CTLR_LE_ENC (defined at subsys/bluetooth/controller/
Kconfig:198) was assigned the value 'n' but got the value 'y'.
This symbol has no prompt, meaning assignments in configuration files
have no effect on it. It can only be set indirectly, via Kconfig
defaults (e.g. in a Kconfig.defconfig file) or through being 'select'ed
or 'imply'd (note: try to avoid Kconfig 'select's except for trivial
promptless "helper" symbols without dependencies, as it ignores
dependencies and forces symbols on).
Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>