arm64: dts: marvell: Fix A37xx UART0 register size

commit c737abc193d16e62e23e2fb585b8b7398ab380d8 upstream.

Armada-37xx UART0 registers are 0x200 bytes wide. Right next to them are
the UART1 registers that should not be declared in this node.

Update the example in DT bindings document accordingly.

Signed-off-by: allen yan <yanwei@marvell.com>
Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>