scsi: dc395x: Remove a few unused variables

scsi: dc395x: Remove a few unused variables

Fixes the following W=1 kernel build warning(s):

 drivers/scsi/dc395x.c: In function ‘data_io_transfer’:
 drivers/scsi/dc395x.c:2400:16: warning: variable ‘data2’ set but not used [-Wunused-but-set-variable]
 drivers/scsi/dc395x.c:2400:6: warning: variable ‘data’ set but not used [-Wunused-but-set-variable]
 drivers/scsi/dc395x.c: In function ‘reselect’:
 drivers/scsi/dc395x.c:2992:5: warning: variable ‘arblostflag’ set but not used [-Wunused-but-set-variable]
 drivers/scsi/dc395x.c: In function ‘doing_srb_done’:
 drivers/scsi/dc395x.c:3393:28: warning: variable ‘dir’ set but not used [-Wunused-but-set-variable]

Link: https://lore.kernel.org/r/20201102142359.561122-18-lee.jones@linaro.org
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Ali Akcaagac <aliakc@web.de>
Cc: Jamie Lenehan <lenehan@twibble.org>
Cc: "C.L. Huang" <ching@tekram.com.tw>
Cc: Erich Chen <erich@tekram.com.tw>
Cc: Kurt Garloff <garloff@suse.de>
Cc: dc395x@twibble.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>