[SCSI] aic79xx: fix shadowed variables, add statics

Redeclared within different if/else blocks, safe to reuse the
original from beginning of function.
drivers/scsi/aic7xxx/aic79xx_core.c:2475:10: warning: symbol 'scbid' shadows an earlier one
drivers/scsi/aic7xxx/aic79xx_core.c:2399:10: originally declared here
drivers/scsi/aic7xxx/aic79xx_core.c:2586:10: warning: symbol 'scbid' shadows an earlier one
drivers/scsi/aic7xxx/aic79xx_core.c:2399:10: originally declared here
drivers/scsi/aic7xxx/aic79xx_core.c:2587:15: warning: symbol 'scb' shadows an earlier one
drivers/scsi/aic7xxx/aic79xx_core.c:2393:13: originally declared here

Use caminfo for the outer declaration, the redeclared version is
iterating over all initiator/target pairs (devices) which.
drivers/scsi/aic7xxx/aic79xx_core.c:8857:23: warning: symbol 'devinfo' shadows an earlier one
drivers/scsi/aic7xxx/aic79xx_core.c:8711:21: originally declared here

Forward declaration was already marked static, make the definition match.
drivers/scsi/aic7xxx/aic79xx_core.c:3693:1: warning: symbol 'ahd_devlimited_syncrate' was not declared. Should it be static?

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>