[SCSI] bnx2i: remove global variable bnx2i_reg_devices

Removed bnx2i_reg_devices as this counter is not really
used in a meaningful way

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Anil Veerabhadrappa <anilgv@broadcom.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>