Update serial drivers to use DT_HAS_<compat>_ENABLED Kconfig symbol
to expose the driver and enable it by default based on devicetree.
We remove 'depend on' Kconfig for symbols that would be implied by
the devicetree node existing.
Signed-off-by: Kumar Gala <galak@kernel.org>
Modifying configuration to enable with gd32vf103
- Add usart definition to devicetree.
- Define USART_STAT as alias of USART_STAT0 if not defined it.
- Enable USART if SOC_SERIES_RISCV_GIGADEVICE_GD32VF103.
Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>