arm64: dts: mediatek: Add mt7986 based Bananapi R3 Mini

Add devicetree for Bananapi R3 Mini SBC.

Key features:
- MediaTek MT7986A(Filogic 830) Quad core ARM Cortex A53
- Wifi 6 2.4G/5G (MT7976C)
- 2G DDR RAM
- 8G eMMC flash
- 128MB Nand flash
- 2x 2.5GbE network port
- 1x M.2 Key B USB interface
- 1x M.2 KEY M PCIe interface
- 1x USB2.0 interface

source: https://wiki.banana-pi.org/Banana_Pi_BPI-R3_MiniCo-developed-by: Eric Woudstra <ericwouds@gmail.com>
Signed-off-by: Eric Woudstra <ericwouds@gmail.com>
Co-developed-by: Tianling Shen <cnsztl@gmail.com>
Signed-off-by: Tianling Shen <cnsztl@gmail.com>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240510095707.6895-3-linux@fw-web.deSigned-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

arch/arm64/boot/dts/mediatek/Makefile

@@ -12,6 +12,7 @@ dtb-$(CONFIG_ARCH_MEDIATEK) += mt7981b-cudy-wr3000-v1.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7981b-xiaomi-ax3000t.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7986a-acelink-ew-7886cax.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7986a-bananapi-bpi-r3.dtb
+dtb-$(CONFIG_ARCH_MEDIATEK) += mt7986a-bananapi-bpi-r3-mini.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7986a-bananapi-bpi-r3-emmc.dtbo
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7986a-bananapi-bpi-r3-nand.dtbo
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7986a-bananapi-bpi-r3-nor.dtbo