KVM: PPC: BOOK3S: Always use the saved DAR value

Although it's optional, IBM POWER cpus always had DAR value set on
alignment interrupt. So don't try to compute these values.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: BOOK3S: Remove open coded make_dsisr in alignment handler

Use make_dsisr instead of open coding it. This also have
the added benefit of handling alignment interrupt on additional
instructions.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>