dt-bindings: nvmem: drop $nodename restriction

Drop $nodename restriction as now mtd partition can also be used as
nvmem provider.
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210312062830.20548-2-ansuelsmth@gmail.com

Documentation/devicetree/bindings/nvmem/nvmem.yaml

@@ -20,9 +20,6 @@ description: |
   storage device.
 
 properties:
-  $nodename:
-    pattern: "^(eeprom|efuse|nvram)(@.*|-[0-9a-f])*$"
-
   "#address-cells":
     const: 1