arm64: dts: ti: k3-am642-hummingboard-t: Convert overlay to board dts

arm64: dts: ti: k3-am642-hummingboard-t: Convert overlay to board dts

SolidRun HummingBoard-T has two options for M.2 connector, supporting
either PCI-E or USB-3.1 Gen 1 - depending on configuration of a mux
on the serdes lane.
The required configurations in device-tree were modeled as overlays.

The USB-3.1 overlay uses /delete-property/ to unset a boolean property
on the usb controller limiting it to USB-2.0 by default.
Overlays can not delete a property from the base dtb, therefore this
overlay is at this time useless.

Convert both overlays into full dts by including the base board dts.
While the pcie overlay was functional, both are converted for a
consistent user experience when selecting between the two mutually
exclusive configurations.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Closes: https://lore.kernel.org/linux-devicetree/CAMuHMdXTgpTnJ9U7egC2XjFXXNZ5uiY1O+WxNd6LPJW5Rs5KTw@mail.gmail.com
Fixes: bbef42084cc1 ("arm64: dts: ti: hummingboard-t: add overlays for m.2 pci-e and usb-3")
Signed-off-by: Josua Mayer <josua@solid-run.com>
Link: https://lore.kernel.org/r/20250101-am64-hb-fix-overlay-v2-1-78143f5da28c@solid-run.com
Signed-off-by: Nishanth Menon <nm@ti.com>