dt-bindings: arm: Drop obsolete brcm,vulcan-soc binding

The Cavium ThunderX2 aka Broadcom Vulcan doesn't use DT, but ACPI, so drop
the SoC binding.

Link: https://patch.msgid.link/20251215213022.3325133-1-robh@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

Documentation/devicetree/bindings/arm/bcm/brcm,vulcan-soc.yaml

@@ -1,24 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-%YAML 1.2
----
-$id: http://devicetree.org/schemas/arm/bcm/brcm,vulcan-soc.yaml#
-$schema: http://devicetree.org/meta-schemas/core.yaml#
-
-title: Broadcom Vulcan
-
-maintainers:
-  - Robert Richter <rrichter@marvell.com>
-
-properties:
-  $nodename:
-    const: '/'
-  compatible:
-    items:
-      - enum:
-          - brcm,vulcan-eval
-          - cavium,thunderx2-cn9900
-      - const: brcm,vulcan-soc
-
-additionalProperties: true
-
-...

MAINTAINERS

@@ -5721,13 +5721,6 @@ S:	Supported
 W:	http://www.marvell.com
 F:	drivers/crypto/cavium/cpt/
 
-CAVIUM THUNDERX2 ARM64 SOC
-M:	Robert Richter <rric@kernel.org>
-L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
-S:	Odd Fixes
-F:	Documentation/devicetree/bindings/arm/bcm/brcm,vulcan-soc.yaml
-F:	arch/arm64/boot/dts/cavium/thunder2-99xx*
-
 CBS/ETF/TAPRIO QDISCS
 M:	Vinicius Costa Gomes <vinicius.gomes@intel.com>
 L:	netdev@vger.kernel.org