From: A. Wilcox <awilfox_at_adelielinux.org>
Date: Thu, 28 Feb 2019 17:27:45 -0600
Kernel 4.14 fails to build with GCC 8 on powerpc64, due to 'in' being
uninitialised in epapr_hypercall*.
This is fixed in commit 186b8f1587c79c2fa04bfa392fdf08 upstream, and
this commit applies cleanly to the 4.14 tree. This commit is already on
the 4.19 branch.