arm: add 6.18 for DTB choice

target/arm/Makefile

@@ -170,7 +170,7 @@ ifeq ($(ADK_TARGET_FS),squashfs)
 	dd conv=notrunc if=$(BUILD_DIR)/root.squashfs of=$(FW_DIR)/$(ROOTFSSQUASHFS)
 endif
 
-ifeq ($(ADK_TARGET_LINUX_KERNEL_VERSION_6_6)$(ADK_TARGET_LINUX_KERNEL_VERSION_6_12)$(ADK_TARGET_LINUX_KERNEL_VERSION_GIT),y)
+ifeq ($(ADK_TARGET_LINUX_KERNEL_VERSION_6_6)$(ADK_TARGET_LINUX_KERNEL_VERSION_6_12)$(ADK_TARGET_LINUX_KERNEL_VERSION_6_18)$(ADK_TARGET_LINUX_KERNEL_VERSION_GIT),y)
 ifeq ($(ADK_TARGET_SYSTEM_QEMU_ARM_VERSATILEPB),y)
 VENDOR:=arm/
 endif