KVM: PPC: Support SC1 hypercalls for PAPR in PR mode

PAPR defines hypercalls as SC1 instructions. Using these, the guest modifies
page tables and does other privileged operations that it wouldn't be allowed
to do in supervisor mode.

This patch adds support for PR KVM to trap these instructions and route them
through the same PAPR hypercall interface that we already use for HV style
KVM.

Signed-off-by: Alexander Graf <agraf@suse.de>