Revert "packet-infiniband: added support for RoCE-v2 (RRocE)"

This reverts commit 07078921e42cae2ff31ac6e11951bb9986ffe5db.

Change-Id: I5b88f0203558c86562694ca841d28314bff336a5
Reviewed-on: https://code.wireshark.org/review/4152
Reviewed-by: Evan Huus <eapache@gmail.com>