KVM: s390: log machine checks more aggressively

KVM: s390: log machine checks more aggressively

KVM will reinject machine checks that happen during guest activity.
From a host perspective this machine check is no longer visible
and even for the guest, the guest might decide to only kill a
userspace program or even ignore the machine check.
As this can be a disruptive event nevertheless, we should log this
not only in the VM debug event (that gets lost after guest shutdown)
but also on the global KVM event as well as syslog.
Consolidate the logging and log with loglevel 2 and higher.

Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Hendrik Brueckner <brueckner@linux.ibm.com>