ipq40xx: disable non-building tel(co Electronics) x1pro

Tel(co Electronics) X1 Pro is preventing ipq40xx generic
from building due to the KERNEL_SIZE.

Whenever bigger kernels are possible, if lzma is supported
is unknown.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

target/linux/ipq40xx/image/generic.mk

@@ -972,6 +972,7 @@ define Device/tel_x1pro
 	IMAGE_SIZE := 31232k
 	IMAGE/sysupgrade.bin := append-kernel | append-rootfs | pad-rootfs | append-metadata
 	DEVICE_PACKAGES := kmod-usb-net-qmi-wwan kmod-usb-serial-option uqmi
+	DEFAULT := n
 endef
 TARGET_DEVICES += tel_x1pro