arm64: dts: imx8ulp-evk: enable lpi2c7 bus

Enable lpi2c7 bus, and enable i2c IO expander.

Reviewed-by: Clark Wang <xiaoning.wang@nxp.com>
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>