dt-bindings: usb: generic-xhci: Allow dma-coherent

Some platforms like Marvell are cache coherent, so allow the
"dma-coherent" property.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250226214231.3745400-1-robh@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>