KVM: x86: introduce sched_in to kvm_x86_ops

sched_in preempt notifier is available for x86, allow its use in
specific virtualization technlogies as well.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --cc arch/x86/include/asm/kvm_host.h
Simple merge

diff --cc arch/x86/kvm/svm.c
Simple merge

diff --cc arch/x86/kvm/vmx.c
Simple merge

diff --cc arch/x86/kvm/x86.c
Simple merge