s390-ccw: print carriage return with new lines

s390-ccw: print carriage return with new lines

The sclp console in the s390 bios writes raw data,
leading console emulators (such as virsh console) to
treat a new line ('\n') as just a new line instead
of as a Unix line feed. Because of this, output
appears in a "stair case" pattern.

Let's print \r\n on every occurrence of a new line
in the string passed to write to amend this issue.

This is in sync with the guest Linux code in
drivers/s390/char/sclp_vt220.c which also does a line feed
conversion in the console part of the driver.

This fixes the s390-ccw and s390-netboot output like
$ virsh start test --console
Domain test started
Connected to domain test
Escape character is ^]
Network boot starting...
                          Using MAC address: 02:01:02:03:04:05
                                                                Requesting information via DHCP:  010

Signed-off-by: Collin L. Walling <walling@linux.vnet.ibm.com>
Message-Id: <1509120893-28054-1-git-send-email-walling@linux.vnet.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>