Multipath TCP kernel patch

[arinc9]

@Mrd @amteza I've posted a tutorial to build OpenWRT with Multipath TCP. Check it here:

[Tutorial] Build OpenWrt with Multipath TCP

This tutorial explains building OpenWrt images with out-of-tree MPTCP (MPTCPv0 & MPTCPv1) support. Disclaimer: We can no longer use out-of-tree MPTCP on OpenWrt 22.03 and newer since upstream MPTCP (supports only MPTCPv1) is included instead. I will write a tutorial for building OpenWrt with upstream MPTCP in the future. There are a few reasons to build your own image to use MPTCP instead of using solutions like OpenMPTCPRouter: Only a few devices are supported. Firmware is heavily bloated,…