arm64: dts: marvell: armada-37xx: add second UART port

Add a node in Armada 37xx DTSI file for the second UART, with a
different compatible due to its extended IP which has some
differences with the first UART already in place.

Make use of this commit to also fully describe the first port and
use the same clear and named interrupt bindings for both ports.

The standard UART (UART0) uses level-interrupts while the extended
UART (UART1) uses edge-triggered interrupts.

Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>