dt-bindings: net: dsa: nxp,sja1105: make spi-cpol optional for sja1110

[ Upstream commit 600f01d ]

Currently, the binding requires 'spi-cpha' for SJA1105 and 'spi-cpol'
for SJA1110.

However, the SJA1110 supports both SPI modes 0 and 2. Mode 2
(cpha=0, cpol=1) is used by the NXP LX2160 Bluebox 3.

On the SolidRun i.MX8DXL HummingBoard Telematics, mode 0 is stable,
while forcing mode 2 introduces CRC errors especially during bursts.

Drop the requirement on spi-cpol for SJA1110.

Fixes: af2eab1 ("dt-bindings: net: nxp,sja1105: document spi-cpol/cpha")
Signed-off-by: Josua Mayer <josua@solid-run.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260409-imx8dxl-sr-som-v2-1-83ff20629ba0@solid-run.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Josua-SR

Documentation/devicetree/bindings/net/dsa/nxp,sja1105.yaml

@@ -131,8 +131,6 @@ allOf:
     else:
       properties:
         spi-cpha: false
-      required:
-        - spi-cpol
 
 unevaluatedProperties: false