ramips: add support for Kroks Rt-Cse SIM Injector DS

Aka Kroks Rt-Cse5 UW DRSIM (KNdRt31R16), ID 1958:
https://kroks.ru/search/?text=1958
See Kroks OpenWrt fork for support of other models:
https://github.com/kroks-free/openwrt

Device specs:
- CPU: MediaTek MT7628AN
- Flash: 16MB SPI NOR
- RAM: 64MB
- Bootloader: U-Boot
- Ethernet: 5x 10/100 Mbps
- 2.4 GHz: b/g/n SoC
- USB: 1x
- SIM-reader: 2x (driven by a dedicated chip with it's own firmware)
- Buttons: reset
- LEDs: 1x Power, 1x Wi-Fi, 12x others (SIM status, Internet, etc.)

Flashing:
- sysupgrade image via stock firmware WEB interface, IP: 192.168.1.254
- U-Boot launches a WEB server if Reset button is held during power up,
  IP: 192.168.1.1

MAC addresses as verified by OEM firmware:
vendor   OpenWrt   source
LAN      eth0      factory 0x4 (label)
2g       wlan0     label

Signed-off-by: Andrey Butirsky <butirsky@gmail.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/target/linux/ramips/dts/mt7628an_kroks_kndrt31r16.dts b/target/linux/ramips/dts/mt7628an_kroks_kndrt31r16.dts
new file mode 100644
index 0000000000..b0b41f0420
--- /dev/null
+++ b/target/linux/ramips/dts/mt7628an_kroks_kndrt31r16.dts
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+
+#include "mt7628an_kroks.dtsi"
+
+/ {
+	compatible = "kroks,kndrt31r16", "mediatek,mt7628an-soc";
+	model = "Kroks KNdRt31R16";
+
+	leds {
+		status {
+			label = "green:status";
+			gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
+		};
+
+		wifi {
+			label = "blue:wifi";
+		};
+	};
+
+	gpio_export {
+		compatible = "gpio-export";
+		#size-cells = <0>;
+
+		usb1power {
+			gpio-export,name = "usb1power";
+			gpio-export,output = <1>;
+			gpios = <&gpio 1 GPIO_ACTIVE_HIGH>;
+		};
+	};
+};
+
+&esw {
+	mediatek,portmap = <0x3e>;
+};
+
+&state_default {
+	gpio {
+		groups = "i2s", "wled_an";
+		function = "gpio";
+	};
+
+	p1led_an {
+		groups = "p1led_an";
+		function = "p1led_an";
+	};
+
+	p2led_an {
+		groups = "p2led_an";
+		function = "p2led_an";
+	};
+
+	p3led_an {
+		groups = "p3led_an";
+		function = "p3led_an";
+	};
+
+	p4led_an {
+		groups = "p4led_an";
+		function = "p4led_an";
+	};
+};