[SCSI] zfcp: Move status accessors from zfcp to SCSI include file.

Move the accessor functions for the scsi_cmnd status from zfcp to the
SCSI include file. Change the interface to the functions to pass the
scsi_cmnd pointer instead of the status pointer.

Signed-off-by: Martin Petermann <martin@linux.vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>