scsi/NCR5380: remove redundant HOSTS_C macro tests

HOSTS_C is always undefined. There is no hosts.c anymore.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Acked-by: Sam Creasey <sammy@sammy.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>