s390: add alignment hints to vector load and store

s390: add alignment hints to vector load and store

BugLink: https://bugs.launchpad.net/bugs/1836857
The z14 introduced alignment hints to increase the performance of
vector loads and stores. The kernel uses an implicit alignmenet
of 8 bytes for the vector registers, set the alignment hint to 3.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
(cherry picked from commit 142c52d7bce45d335f48d53fdbf428bb15cf3924)
Signed-off-by: Frank Heimes <frank.heimes@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>