drivers: bluetooth: hci: Remove prompt on non user selectable symbols

Most of BT_FOO symbols that are designed to select the hci driver
implementation which will drive the comunication with controller are
selected based on device tree compatible and should not be made available
as an configurable option to the user.
To do this, remove the prompt on these symbols.

Signed-off-by: Erwan Gouriou <erwan.gouriou@st.com>