generic: do not attempt to build kmod-usbip

kmod-usbip is broken since the last kernel update.

targets/generic

@@ -2,6 +2,8 @@ config '# CONFIG_TARGET_ROOTFS_INITRAMFS is not set'
 
 config 'CONFIG_ALL_NONSHARED=y'
 
+config '# CONFIG_PACKAGE_usbip is not set' # fails to build
+
 config 'CONFIG_BUSYBOX_CUSTOM=y'
 config 'CONFIG_BUSYBOX_CONFIG_SHA256SUM=y'
 config '# CONFIG_BUSYBOX_CONFIG_FEATURE_PREFER_IPV4_ADDRESS is not set'