arm64: dts: ti: k3-am654: Add Support for eMMC host controller

Add support for the Secure Digital Host Controller Interface (SDHCI)
present on TI's AM654 SOCs. It is compatible with eMMC5.1 Host
Specifications.

Enable only upto HS200 speed mode.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>