arm64: dts: ti: k3-am62p/j722s: Remove HS400 support from common

arm64: dts: ti: k3-am62p/j722s: Remove HS400 support from common

Since eMMC HS400 has been descoped for J722s due to errata i2478 [0]
and is supported for AM62Px device, remove eMMC HS400 support from
common-main.dtsi and include only in am62p-main.dtsi.

[0] https://www.ti.com/lit/pdf/sprz575

Signed-off-by: Judith Mendez <jm@ti.com>
Reviewed-by: Andrew Davis <afd@ti.com>
Reviewed-by: Moteen Shah <m-shah@ti.com>
Link: https://patch.msgid.link/20250908235207.473628-2-jm@ti.com
Signed-off-by: Nishanth Menon <nm@ti.com>