[ewg] cxgb3/cxgb4 compat backports for RHEL7.5

[Arjun Vynipadath]

Hey Vlad,

Please pull the following compat commit of RHEL7.5 backports from my for-vlad branch of
https://github.com/arjunvynipadath/compat
---------------------------------------------
commit 684448d70af261dba369caf7a544048751cfd019
Author: Arjun Vynipadath <arjun at chelsio.com>
Date:   Mon Jun 25 13:02:02 2018 +0530

    rdma.m4: Added compat headers for cxgb3/iw_cxgb3/cxgb4/iw_cxgb4

    Signed-off-by: Arjun Vynipadath <arjun at chelsio.com>

----------------------------------------------

Thanks,
Arjun.