Mr. Grep reports that the EDMA chain/unchain calls are unused.
Same in the old 2.6.10 code; there seems to be no value in
those routines.  Delete!  Saves a few bytes.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>