ARM64: dts: marvell: cn9310: Use appropriate label for spi1 pins

The CN9130-DB uses the SPI1 interface but had the pinctrl node labelled
as "cp0_spi0_pins". Use the label "cp0_spi1_pins" and update the node
name to "cp0-spi-pins-1" to avoid confusion with the pinctrl options for
SPI0.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>