spi: dt-bindings: cdns,qspi-nor: Be more descriptive regarding what this controller is

Despite being very common in commit logs, SPI NOR controllers simply do
not exist. At least, they are not as specific as the name implies. There
are SPI memory controllers which are indeed "specialized" and optimized
for handling "memories", but most of them are just generic and accept
almost any kind of opcode, address, dummy and data cycles, making them
as suitable for NANDs than NORs.

Furthermore, this controller supports any kind of bus, from single to
octal NAND, so make it clear.

Also add a comment to mention that the initial compatible naming is too
specific (but obviously kept for backward compatibility reasons).

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250319094651.1290509-2-miquel.raynal@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: miquelraynal

Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml

@@ -4,7 +4,7 @@
 $id: http://devicetree.org/schemas/spi/cdns,qspi-nor.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Cadence Quad SPI controller
+title: Cadence Quad/Octal SPI controller
 
 maintainers:
   - Vaishnav Achath <vaishnav.a@ti.com>
@@ -76,6 +76,9 @@ properties:
               - ti,am654-ospi
               - ti,k2g-qspi
               - xlnx,versal-ospi-1.0
+          # The compatible is qspi-nor for historical reasons but such
+          # controllers are meant to be used with flashes of all kinds,
+          # ie. also NAND flashes, not only NOR flashes.
           - const: cdns,qspi-nor
       - const: cdns,qspi-nor