The STM32U0xx devices support only SWD.
Add swd transport in the target file.
Remove swd transport from the associated board files.
Change-Id: I2d31856951d15fcf2d1986ee5b1b31464e68db1c
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/9427
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Tested-by: jenkins
Reviewed-by: Ahmed Haoues <ahmed.haoues@st.com>