[SCSI] scsi:hosts.c Fix warning: variable 'rval' set but not used

The below patch fixes a warning message generated by gcc 4.6.0
  CC      drivers/scsi/hosts.o
drivers/scsi/hosts.c: In function 'scsi_host_alloc':
drivers/scsi/hosts.c:328:6: warning: variable 'rval' set but not used

Fix this by removing the rval but placing a printk warning where it
would have been set.

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>