[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/aha1740.c b/drivers/scsi/aha1740.c
index 73f33e7..8f85dcc 100644
--- a/drivers/scsi/aha1740.c
+++ b/drivers/scsi/aha1740.c
@@ -347,7 +347,7 @@
 {
 	unchar direction;
 	unchar *cmd = (unchar *) SCpnt->cmnd;
-	unchar target = SCpnt->device->id;
+	unchar target = scmd_id(SCpnt);
 	struct aha1740_hostdata *host = HOSTDATA(SCpnt->device->host);
 	unsigned long flags;
 	void *buff = SCpnt->request_buffer;