ARM: dts: exynos: Move common Exynos4x12 definitions to exynos4x12.dtsi

In preparation for the re-introduction of the Exynos4212, move
their shared definitions to a separate file. Rename the pinctrl
definitions accordingly, and adapt the Exynos4412 DTSI to these
changes.

This reverts part of commit bca9085e ("ARM: dts: exynos:
remove Exynos4212 support (dead code)").
Signed-off-by: Artur Weber <aweber.kernel@gmail.com>
Link: https://lore.kernel.org/r/20230501195525.6268-10-aweber.kernel@gmail.comSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

arch/arm/boot/dts/exynos4412-pinctrl.dtsi → arch/arm/boot/dts/exynos4x12-pinctrl.dtsi

 // SPDX-License-Identifier: GPL-2.0
 /*
- * Samsung's Exynos4412 SoCs pin-mux and pin-config device tree source
+ * Samsung's Exynos4x12 SoCs pin-mux and pin-config device tree source
  *
  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
  *		http://www.samsung.com
  *
- * Samsung's Exynos4412 SoCs pin-mux and pin-config optiosn are listed as device
+ * Samsung's Exynos4x12 SoCs pin-mux and pin-config optiosn are listed as device
  * tree nodes are listed in this file.
  */