dt-bindings: serial: Convert altr,uart-1.0 to DT schema

Convert the Altera JTAG UART binding to DT schema. The "ALTR,uart-1.0"
compatible has long been deprecated, so drop it.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

Documentation/devicetree/bindings/serial/altera_uart.txt

@@ -1,8 +0,0 @@
-Altera UART
-
-Required properties:
-- compatible : should be "ALTR,uart-1.0" <DEPRECATED>
-- compatible : should be "altr,uart-1.0"
-
-Optional properties:
-- clock-frequency : frequency of the clock input to the UART

Documentation/devicetree/bindings/serial/altr,uart-1.0.yaml

@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/altr,uart-1.0.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Altera UART
+
+maintainers:
+  - Dinh Nguyen <dinguyen@kernel.org>
+
+allOf:
+  - $ref: /schemas/serial/serial.yaml#
+
+properties:
+  compatible:
+    const: altr,uart-1.0
+
+  clock-frequency:
+    description: Frequency of the clock input to the UART.
+
+required:
+  - compatible
+
+unevaluatedProperties: false