s390-ccw: refactor IPL structs

s390-ccw: refactor IPL structs

ECKD DASDs have different IPL structures for CDL and LDL
formats. The current Ipl1 and Ipl2 structs follow the CDL
format, so we prepend "EckdCdl" to them. Boot info for LDL
has been moved to a new struct: EckdLdlIpl1.

Signed-off-by: Collin L. Walling <walling@linux.vnet.ibm.com>
Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>