Merge commit '6ba1bc826d160fe4f32bcb188687dcca4bdfaf3d' into arch-arm64

Backmerge from mainline commit that introduced a trivial conflict in
arch/arm64/kernel/process.c - a bunch of functions removed next to the
place where kernel_thread() used to be.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>