scsi_logging: return void for dev_printk() functions

dev_printk() is now a void function, so the related functions
scmd_printk() and sdev_prefix_printk() should be made void, too.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

include/scsi/scsi_device.h

@@ -237,14 +237,14 @@ struct scsi_dh_data {
  * like scmd_printk, but the device name is passed in
  * as a string pointer
  */
-__printf(4, 5) int
+__printf(4, 5) void
 sdev_prefix_printk(const char *, const struct scsi_device *, const char *,
 		const char *, ...);
 
 #define sdev_printk(l, sdev, fmt, a...)				\
 	sdev_prefix_printk(l, sdev, NULL, fmt, ##a)
 
-__printf(3, 4) int
+__printf(3, 4) void
 scmd_printk(const char *, const struct scsi_cmnd *, const char *, ...);
 
 #define scmd_dbg(scmd, fmt, a...)					   \