arm64: dts: imx8ulp-evk: add 100MHz/200MHz pinctrl setting for eMMC

Add 100MHz and 200MHz pinctrl setting for eMMC, and enable 8 bit bus mode
to config the eMMC work at HS400ES mode.

Also update to use Standard Drive Strength for USDHC pad to get a better
signal quality per Hardware team suggests.

Reviewed-by: Sherry Sun <sherry.sun@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>