[SCSI] be2iscsi: memset wrb for ring create

   This patch fixes a situation when  wrb was not being memset to zero
before being used

Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>