boards: nucleo_h755zi_q: fix debugging

This fix uses the stm32h745i-disco openocd configuration instead of the
st_nucleo_h745zi configuration as the latter seems to be broken in
openocd as shipped by zephyr-sdk-0.17.0.

Signed-off-by: Martin Thiede <martin.thiede@accenture.com>
1 file changed