Subject: linux-next: Signed-off-by missing for commit in the dma-mapping-fixes tree

From: Stephen Rothwell <[email-masked]>
Date: Thu, 24 Jan 2019 07:43:16 +1100

Hi Christoph,

Commit

  e31614683919 ("Revert "arm64/xen: fix xen-swiotlb cache flushing"")

is missing a Signed-off-by from its author and committer.

Reverts are commits too.  Also, it can be useful to have an explanation
for the revert in the commit message.

-- 
Cheers,
Stephen Rothwell