arm64: dts: imx8mp: Adjust ECSPI1 pinmux on i.MX8M Plus DHCOM

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

Fixes: 8d671269 ("arm64: dts: imx8mp: Add support for DH electronics i.MX8M Plus DHCOM and PDK2")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@denx.de>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Shawn Guo <shawnguo@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Shawn Guo <shawnguo@kernel.org>