lantiq: xrx200: mark subtarget as source-only

The current problems blocking the switch to the kernel 5.15 are
related to the GSWIP driver. This driver is only used by the
xrx200 subtarget. The other subtargets are unaffected by this
problem.

Signed-off-by: Aleksander Jan Bajkowski <[email protected]>

target/linux/lantiq/xrx200/target.mk

@@ -1,7 +1,7 @@
 ARCH:=mips
 SUBTARGET:=xrx200
 BOARDNAME:=XRX200
-FEATURES+=atm nand ramdisk
+FEATURES+=atm nand ramdisk source-only
 CPU_TYPE:=24kc
 
 DEFAULT_PACKAGES+=kmod-leds-gpio \