kvm: svm: Only propagate next_rip when guest supports it

Currently we always write the next_rip of the shadow vmcb to
the guests vmcb when we emulate a vmexit. This could confuse
the guest when its cpuid indicated no support for the
next_rip feature.

Fix this by only propagating next_rip if the guest actually
supports it.

Cc: Bandan Das <bsd@redhat.com>
Cc: Dirk Mueller <dmueller@suse.com>
Tested-By: Dirk Mueller <dmueller@suse.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>