lpuart1 is the default port used by ST-Link VPC.
Update board description to match out of box board configuration.
Fixes#12092
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
STM32 uart Kconfig instance flags were not following
same naming scheme than other drivers (i2c, spi, ..)
Update driver to use UART_X instead of UART_STM32_PORT_X
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>