Revert "driver core: check start node in klist_iter_init_node"

This reverts commit a15d49fd as that
patch broke the build.

Cc: Hannes Reinecke <hare@suse.de>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>