s390-bios: Support for running format-0/1 channel programs

s390-bios: Support for running format-0/1 channel programs

Introduce a library function for executing format-0 and format-1
channel programs and waiting for their completion before continuing
execution.

Add cu_type() to channel io library. This will be used to query control
unit type which is used to determine if we are booting a virtio device or a
real dasd device.

Signed-off-by: Jason J. Herne <jjherne@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Message-Id: <1554388475-18329-9-git-send-email-jjherne@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>