GitLab

Switches default on the NUCLEO_WL55 board to use the HSE oscillator powered
from PB0_VDDTCXO pin.

Build-time configuration can select from MSI internal oscillator (previous
default), HSE via crystal, or HSE bypass with TCXO powered from PB0_VDDTCXO
pin (new default)
Signed-off-by: Angus Gratton <angus@redyak.com.au>