scsi: aic94xx: Remove code that has been unused for at least 13 years

scsi: aic94xx: Remove code that has been unused for at least 13 years

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

 drivers/scsi/aic94xx/aic94xx_dump.c:731: warning: expecting prototype for asd_dump_ddb_site(). Prototype was for asd_dump_target_ddb() instead
 drivers/scsi/aic94xx/aic94xx_dump.c:875: warning: expecting prototype for ads_dump_seq_state(). Prototype was for asd_dump_seq_state() instead

Link: https://lore.kernel.org/r/20210303144631.3175331-22-lee.jones@linaro.org
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: David Chaw <david_chaw@adaptec.com>
Cc: Luben Tuikov <luben_tuikov@adaptec.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>