dt-bindings: mtd: spi-nor: clarify the need for spi-nor compatibles

Most SPI NOR devices do not require a specific compatible, their ID can
in general be discovered with the JEDEC READ ID opcode. In this case,
only the "jedec,spi-nor" generic compatible is expected. Clarify this
information in the compatible description to (i) help device-tree
writers and (ii) prevent further attempts to extend this list with
useless information.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230616140054.2788684-1-miquel.raynal@bootlin.com
[ta: s/JEDEC/JEDEC SFDP for clarity and s/JEDEC READ ID/READ ID as
the opcode is not part of the JEDEC SFDP standard.]
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>

Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml

@@ -43,8 +43,10 @@ properties:
           - const: jedec,spi-nor
       - const: jedec,spi-nor
     description:
-      Must also include "jedec,spi-nor" for any SPI NOR flash that can be
-      identified by the JEDEC READ ID opcode (0x9F).
+      SPI NOR flashes compatible with the JEDEC SFDP standard or which may be
+      identified with the READ ID opcode (0x9F) do not deserve a specific
+      compatible. They should instead only be matched against the generic
+      "jedec,spi-nor" compatible.
 
   reg:
     minItems: 1