build: filter out kmod-ipt-offload from the default selection on targets that do not support it

Signed-off-by: Felix Fietkau <nbd@nbd.name>

include/target.mk

@@ -51,6 +51,10 @@ else
   endif
 endif
 
+ifneq ($(filter 3.18 4.4 4.9,$(KERNEL_PATCHVER)),)
+  DEFAULT_PACKAGES.router:=$(filter-out kmod-ipt-offload,$(DEFAULT_PACKAGES.router))
+endif
+
 # Add device specific packages (here below to allow device type set from subtarget)
 DEFAULT_PACKAGES += $(DEFAULT_PACKAGES.$(DEVICE_TYPE))