[SCSI] use scmd_id(), scmd_channel() throughout code

Wrap a highly common idiom.  Makes the code easier to read, helps pave
the way for sdev->{id,channel} removal, and adds a token that can easily
by grepped-for in the future.

There are a couple sdev_id() and scmd_printk() updates thrown in as well.

Rejections fixed up and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/NCR53c406a.c b/drivers/scsi/NCR53c406a.c
index e1f2246..1353769 100644
--- a/drivers/scsi/NCR53c406a.c
+++ b/drivers/scsi/NCR53c406a.c
@@ -710,7 +710,7 @@
 
 	/* We are locked here already by the mid layer */
 	REG0;
-	outb(SCpnt->device->id, DEST_ID);	/* set destination */
+	outb(scmd_id(SCpnt), DEST_ID);	/* set destination */
 	outb(FLUSH_FIFO, CMD_REG);	/* reset the fifos */
 
 	for (i = 0; i < SCpnt->cmd_len; i++) {