dt-bindings: firmware: brcm,kona-smc: convert to YAML

Convert Broadcom Kona family Secure Monitor bounce buffer bindings
to DT schema.

Changes during conversion:
- move from misc to firmware subdirectory
- add used, but previously undocumented SoC-specific compatibles
- drop deprecated compatibles (they've been deprecated for ~10 years)

Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Stanislav Jakubek <[e-mail]>
Link: https://lore.kernel.org/r/20230618151308.GA23586@standask-GA-A55M-S2HP
Signed-off-by: Florian Fainelli <[e-mail]>

Documentation/devicetree/bindings/firmware/brcm,kona-smc.yaml

···
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/firmware/brcm,kona-smc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom Kona family Secure Monitor bounce buffer
+
+description:
+  A bounce buffer used for non-secure to secure communications.
+
+maintainers:
+  - Florian Fainelli <[e-mail]>
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - brcm,bcm11351-smc
+          - brcm,bcm21664-smc
+          - brcm,bcm23550-smc
+      - const: brcm,kona-smc
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    smc@3404c000 {
+        compatible = "brcm,bcm11351-smc", "brcm,kona-smc";
+        reg = <0x3404c000 0x400>; /* 1 KiB in SRAM */
+    };
+...

Documentation/devicetree/bindings/misc/brcm,kona-smc.txt

···
-Broadcom Secure Monitor Bounce buffer
------------------------------------------------------
-This binding defines the location of the bounce buffer
-used for non-secure to secure communications.
-
-Required properties:
-- compatible : "brcm,kona-smc"
-- DEPRECATED: compatible : "bcm,kona-smc"
-- reg : Location and size of bounce buffer
-
-Example:
-	smc@3404c000 {
-		compatible = "brcm,bcm11351-smc", "brcm,kona-smc";
-		reg = <0x3404c000 0x400>; //1 KiB in SRAM
-	};