hw/s390x/sclp: update LOADPARM in SCP Info

LOADPARM has two copies:
1. in SCP Information Block
2. in IPL Information Parameter Block

So, update SCLP intrinsics now. We always store LOADPARM in SCP
information block even if we don't have a valid IPL Information
Parameter Block.

Initial patch from Eugene (jno) Dvurechenski.

Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
