pc-bios/s390-ccw: Move ebc2asc to sclp.c

We will later need this array in a file that we will link to the
netboot code, too. Since there is some ebcdic conversion done
in sclp_get_loadparm_ascii(), the sclp.c file seems to be a good
candidate.

Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1499863793-18627-3-git-send-email-thuth@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>