kvm: introduce kvm_mce_in_progress

Share same error handing, and rename this function after
MCIP (Machine Check In Progress) flag.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Jin Dongming <jin.dongming@np.css.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
