realtek: Add Makefile for RTL839x sub-architecture

Adds the initial Makefile for the RTL839x sub-architecture.

Signed-off-by: Birger Koblitz <[email protected]>

target/linux/realtek/rtl839x/target.mk

@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0-only
+ARCH:=mips
+SUBTARGET:=rtl839x
+CPU_TYPE:=24kc
+BOARD:=realtek
+BOARDNAME:=Realtek MIPS RTL839X
+
+KERNEL_PATCHVER:=5.10
+
+define Target/Description
+	Build firmware images for Realtek RTL839x based boards.
+endef
+