[FS#1083] ar71xx Kernel 4.9 PPTP Passthrough not working

[LEDE Bugs]

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

User who did this - nouman8 (nouman8) 

Attached to Project - LEDE Project
Summary - ar71xx Kernel 4.9  PPTP Passthrough not working
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Critical
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - today i compiled for my TP-Link mr3420 v2 with Kerenl 4.9 by simply changing the KERNEL_PATCHVER:=4.4 to KERNEL_PATCHVER:=4.9 in target/linux/ar71xx/Makefile , everything works good so far except i am not able to connect to the VPN which was working good previously with 4.4 kernel compiled lede a week back.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1083