[FS#1479] ramips: sysupgrade and factory images built from master after 4.14 upgrade are not built due to size

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Dan Everton (deverton) 

Attached to Project - OpenWrt/LEDE Project
Summary - ramips: sysupgrade and factory images built from master after 4.14 upgrade are not built due to size
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Medium
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - Trying to build a custom image for a TP-Link RE350 V1 and running into issues with the sysupgrade and factory images being too large and failing the tplink safe size check.

I can build the images with the below diffconfig, but that's obviously taking it too far as it breaks dmesg.

CONFIG_TARGET_ramips=y
CONFIG_TARGET_ramips_mt7621=y
CONFIG_TARGET_ramips_mt7621_DEVICE_re350-v1=y
# CONFIG_KERNEL_CRASHLOG is not set
# CONFIG_KERNEL_DEBUG_FS is not set
# CONFIG_KERNEL_DEBUG_INFO is not set
# CONFIG_KERNEL_DEBUG_KERNEL is not set
# CONFIG_KERNEL_KALLSYMS is not set
# CONFIG_KERNEL_MAGIC_SYSRQ is not set
# CONFIG_KERNEL_PRINTK is not set
# CONFIG_KERNEL_PRINTK_TIME is not set
# CONFIG_KERNEL_SWAP is not set
# CONFIG_PACKAGE_MAC80211_DEBUGFS is not set

More information can be found at the following URL:
https://bugs.openwrt.org/index.php?do=details&task_id=1479