spi: dt-bindings: snps,dw-apb-ssi: Document Axiado AX3005

spi: dt-bindings: snps,dw-apb-ssi: Document Axiado AX3005

The Axiado AX3005 SPI controller is software-compatible with the
Synopsys DesignWare APB SSI 1.01a programming interface.

Document the "axiado,ax3005-spi" SoC-specific compatible with
"snps,dwc-ssi-1.01a" as its fallback. This preserves identification of
the AX3005 integration while allowing the controller to use the
existing DesignWare APB SSI support.

Signed-off-by: Swark Yang <syang@axiado.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260805-upstrea-ax3005-spi-v4-v4-1-5b8bc11cb841@axiado.com
Signed-off-by: Mark Brown <broonie@kernel.org>