scsi: Remove the definition of VLC_SA_RECEIVE_CREDENTIAL

The symbolic name VLC_SA_RECEIVE_CREDENTIAL is not used anywhere in the
kernel. Additionally, since SPC 5 the RECEIVE CREDENTIAL command is
obsolete. The VLC_SA_RECEIVE_CREDENTIAL definition is misleading since
it occurs outside the list of other variable length CDB service action
codes (READ_32, WRITE_32, ...). Hence remove this definition.

References: commit e9ccc998 ("[SCSI] Add missing SPC-4 CDB and
MAINTENANCE_[IN,OUT] service action definitions")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>