dt-bindings: net: smsc,lan91c111 convert to schema

Convert the smsc lan91c9x and lan91c1xx controller device tree
bindings documentation to json-schema.
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220331154536.1544220-2-rui.silva@linaro.org

Documentation/devicetree/bindings/net/smsc,lan91c111.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/smsc,lan91c111.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Smart Mixed-Signal Connectivity (SMSC) LAN91C9x/91C1xx Controller
+
+maintainers:
+  - Nicolas Pitre <nico@fluxnic.net>
+
+allOf:
+  - $ref: ethernet-controller.yaml#
+
+properties:
+  compatible:
+    const: smsc,lan91c111
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  reg-shift: true
+
+  reg-io-width:
+    enum: [ 1, 2, 4 ]
+    default: 4
+
+  reset-gpios:
+    description: GPIO connected to control RESET pin
+    maxItems: 1
+
+  power-gpios:
+    description: GPIO connect to control PWRDWN pin
+    maxItems: 1
+
+  pxa-u16-align4:
+    description: put in place the workaround the force all u16 writes to be
+      32 bits aligned
+    type: boolean
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    ethernet@4010000 {
+          compatible = "smsc,lan91c111";
+          reg = <0x40100000 0x10000>;
+          phy-mode = "mii";
+          interrupts = <GIC_SPI 116 IRQ_TYPE_LEVEL_HIGH>;
+          reg-io-width = <2>;
+    };

Documentation/devicetree/bindings/net/smsc-lan91c111.txt

-SMSC LAN91c111 Ethernet mac
-
-Required properties:
-- compatible = "smsc,lan91c111";
-- reg : physical address and size of registers
-- interrupts : interrupt connection
-
-Optional properties:
-- phy-device : see ethernet.txt file in the same directory
-- reg-io-width : Mask of sizes (in bytes) of the IO accesses that
-  are supported on the device.  Valid value for SMSC LAN91c111 are
-  1, 2 or 4.  If it's omitted or invalid, the size would be 2 meaning
-  16-bit access only.
-- power-gpios: GPIO to control the PWRDWN pin
-- reset-gpios: GPIO to control the RESET pin
-- pxa-u16-align4 : Boolean, put in place the workaround the force all
-		   u16 writes to be 32 bits aligned