dt-bindings: net: snps,dwmac: Enable burst length properties for more compatibles

With 'unevaluatedProperties' support implemented, the properties
'snps,pbl', 'snps,txpbl', and 'snps,rxpbl' are not allowed in the
examples for some of the DWMAC versions:

Documentation/devicetree/bindings/net/intel,dwmac-plat.example.dt.yaml: ethernet@3a000000: Unevaluated properties are not allowed ('snps,pbl', 'mdio0' were unexpected)
Documentation/devicetree/bindings/net/stm32-dwmac.example.dt.yaml: ethernet@5800a000: Unevaluated properties are not allowed ('reg-names', 'snps,pbl' were unexpected)
Documentation/devicetree/bindings/net/stm32-dwmac.example.dt.yaml: ethernet@40028000: Unevaluated properties are not allowed ('reg-names', 'snps,pbl' were unexpected)
Documentation/devicetree/bindings/net/stm32-dwmac.example.dt.yaml: ethernet@40027000: Unevaluated properties are not allowed ('reg-names', 'snps,pbl' were unexpected)
Documentation/devicetree/bindings/net/toshiba,visconti-dwmac.example.dt.yaml: ethernet@28000000: Unevaluated properties are not allowed ('snps,txpbl', 'snps,rxpbl', 'mdio0' were unexpected)

This appears to be an oversight, so fix it by allowing the properties
on the v3.50a, v4.10a, and v4.20a versions of the DWMAC.

Cc: "David S. Miller" <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Alexandre Torgue <[email protected]>
Cc: Giuseppe Cavallaro <[email protected]>
Cc: Jose Abreu <[email protected]>
Cc: [email protected]
Signed-off-by: Rob Herring <[email protected]>
Reviewed-by: Thierry Reding <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: robherring

Documentation/devicetree/bindings/net/snps,dwmac.yaml

@@ -326,6 +326,9 @@ allOf:
               - ingenic,x1600-mac
               - ingenic,x1830-mac
               - ingenic,x2000-mac
+              - snps,dwmac-3.50a
+              - snps,dwmac-4.10a
+              - snps,dwmac-4.20a
               - snps,dwxgmac
               - snps,dwxgmac-2.10
               - st,spear600-gmac