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

 drivers/scsi/aic7xxx/aic79xx_core.c: In function ‘ahd_dump_sglist’:
 drivers/scsi/aic7xxx/aic79xx_core.c:1738:14: warning: variable ‘len’ set but not used [-Wunused-but-set-variable]
 1738 | uint32_t len;
 | ^~~
 drivers/scsi/aic7xxx/aic79xx_core.c: In function ‘ahd_handle_seqint’:
 drivers/scsi/aic7xxx/aic79xx_core.c:1911:26: warning: variable ‘tinfo’ set but not used [-Wunused-but-set-variable]
 1911 | struct ahd_transinfo *tinfo;
 | ^~~~~
 drivers/scsi/aic7xxx/aic79xx_core.c: In function ‘ahd_handle_transmission_error’:
 drivers/scsi/aic7xxx/aic79xx_core.c:2672:8: warning: variable ‘lqistat2’ set but not used [-Wunused-but-set-variable]
 2672 | u_int lqistat2;
 | ^~~~~~~~
 drivers/scsi/aic7xxx/aic79xx_core.c: In function ‘ahd_update_pending_scbs’:
 drivers/scsi/aic7xxx/aic79xx_core.c:4221:31: warning: variable ‘tinfo’ set but not used [-Wunused-but-set-variable]
 4221 | struct ahd_initiator_tinfo *tinfo;
 | ^~~~~

Link: https://lore.kernel.org/r/20200721164148.2617584-3-lee.jones@linaro.org
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>