[ewg] Please add following "known issue" for bug # 2619

[Davis, Arlin R]

Vlad, 

Please add the following to "3. Known Issues" section for OFED 4.8 release notes for GA.

19. Bug 2619:  IPoIB interface fails on RHEL 7.2 using FW release 12.18.2000 with mlx5 MT_2180110032 adapter

Issue: Trying to bring ib0 interface fails with mlx5_0:mlx5_ib_post_send:  
 	 ib0: multicast join failed for ff12:401b:ffff:0000:0000:0000:ffff:ffff, status -22
Workaround: revert MT_2180110032 firmware from 12.18.2000 to 12.12.1100.  

20. NFSoRDMA is not supported

Thanks,

Arlin