dt-bindings: serial: brcm,bcm2835-aux-uart: convert to dtschema

Convert the Broadcom BCM2835 Auxiliary UART to newer DT schema.
Created DT schema based on the .txt file which had
`compatible`, `reg` `clocks` and `interrupts` as the
required properties. This binding is used by Broadcom BCM2835
SOC used in some Raspberry PI boards.
Changes from original file:
Implemented complete example which the original txt binding lacked.

Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Pratik Farkase <pratik.farkase@wsisweden.com>
Link: https://lore.kernel.org/r/20240425162554.13576-1-pratik.farkase@wsisweden.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/brcm,bcm2835-aux-uart.txt

@@ -1,18 +0,0 @@
-* BCM2835 AUXILIAR UART
-
-Required properties:
-
-- compatible: "brcm,bcm2835-aux-uart"
-- reg: The base address of the UART register bank.
-- interrupts: A single interrupt specifier.
-- clocks: Clock driving the hardware; used to figure out the baud rate
-  divisor.
-
-Example:
-
-	uart1: serial@7e215040 {
-		compatible = "brcm,bcm2835-aux-uart";
-		reg = <0x7e215040 0x40>;
-		interrupts = <1 29>;
-		clocks = <&aux BCM2835_AUX_CLOCK_UART>;
-	};

Documentation/devicetree/bindings/serial/brcm,bcm2835-aux-uart.yaml

@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/brcm,bcm2835-aux-uart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: BCM2835 AUXILIARY UART
+
+maintainers:
+  - Pratik Farkase <pratikfarkase94@gmail.com>
+  - Florian Fainelli <florian.fainelli@broadcom.com>
+  - Stefan Wahren <wahrenst@gmx.net>
+
+allOf:
+  - $ref: serial.yaml
+
+properties:
+  compatible:
+    const: brcm,bcm2835-aux-uart
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/bcm2835-aux.h>
+    serial@7e215040 {
+        compatible = "brcm,bcm2835-aux-uart";
+        reg = <0x7e215040 0x40>;
+        interrupts = <1 29>;
+        clocks = <&aux BCM2835_AUX_CLOCK_UART>;
+    };