The poor device_create function is a victim of chronic fiddling.
After the removal of class_simple, there are several states the kernel
has gone through.

  cdc4	
	class_device_create with four arguments, found before
	2.6.15-rc7 or so.

  cdc5
	class_device_create with five arguments

  dcd
	device_create_drvdata was around by the time
	class_device_create was finally removed in commit
	c3b19ff06e0808555403491d61e8f0cbbb53e933 (which appears in
	v2.6.26-rc1~99^2~1).

Then device_create_drvdata got removed, and callers of
device_create_drvdata were just switched to device_create without
further modification.

  dc NEW
  	device_create with 5 arguments

commit 7fb6b5d51daf3613045258ee8add07022d8c39d3
Author: Greg Kroah-Hartman <gregkh@suse.de>
Date:   Mon Jul 21 20:03:34 2008 -0700

    device create: remove device_create_drvdata
    
    Now that the tree is cleaned up, device_create_drvdata can be safely
    removed.
    
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

commit 3ee074bf432d24a92894397ac48ad2f2bb95efdc
Author: Greg Kroah-Hartman <gregkh@suse.de>
Date:   Mon Jul 21 20:03:34 2008 -0700

    device create: ide: convert device_create_drvdata to device_create
    
    Now that device_create() has been audited, rename things back to the
    original call to be sane.
    
    Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>