drivers: serial: add XMC seris UART support

Add infineon XMC4 series UART support. Driver supports
only poll mode using XMCLib.

Out of 4 available UART's on SoC, only UART1 is confgired
by default in UART mode until GPIO & pinctrl support.

Signed-off-by: Parthiban Nallathambi <parthiban@linumiz.com>
7 files changed