ARM: dts: imx: Adjust ECSPI1 pinmux on i.MX8M Plus DHCOM

The ECSPI1 is on I2C1/I2C2 pins of the SoC, update the pinmux accordingly.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@denx.de>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: uboot-imx <uboot-imx@nxp.com>