[SCSI] sd: make comment and printk string match code

Adapt comment and printk string after renaming sd_init_command to sd_prep_fn
Adapt comment and printk string after renaming sd_attach to sd_probe

Signed-off-by: Petr Uzel <petr.uzel@suse.cz>
Acked-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>