scsi: zfcp: remove unused ERP enum values

All constant defines were introduced with v2.6.0 history commit ea127f975424
("[PATCH] s390 (7/7): zfcp host adapter.") and refactored into enums with
commit 287ac01a ("[SCSI] zfcp: Cleanup code in zfcp_erp.c").

ZFCP_STATUS_ERP_DISMISSING and ZFCP_ERP_STEP_FSF_XCONFIG were never used.

v2.6.27 commit 287ac01a ("[SCSI] zfcp: Cleanup code in zfcp_erp.c")
removed the use of ZFCP_ERP_ACTION_READY on refactoring
zfcp_erp_action_exists() to now only check adapter->erp_running_head but no
longer adapter->erp_ready_head. The same commit could have changed the
function return type from int to "enum zfcp_erp_act_state".
ZFCP_ERP_ACTION_READY was never used outside of zfcp_erp_action_exists().

Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>