spi: dt-bindings: cadence: Add Marvell overlay bindings documentation for Cadence XSPI

Add new bindings for the v2 Marvell xSPI overlay: marvell,cn10-xspi-nor
compatible string. This new compatible string distinguishes between the
original and modified xSPI block.

Also add an optional base for the xfer register set with an additional
reg field to allocate the xSPI Marvell overlay XFER block.

Signed-off-by: Witold Sadowski <wsadowski@marvell.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20240724154739.582367-2-wsadowski@marvell.com


Signed-off-by: Mark Brown <broonie@kernel.org>