ST-Link VPC is wired to UART_1.
Console should be assigned to this peripheral to be available.
By default UART_1 is assigned to m7 core and not available to m4.
This commit does not change this, but makes it easier to change
UART_1 assignment from m7 to m4 core.
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>