Add support for DM646x SoC (a.k.a DaVinci HD) and its Evalution
Module (EVM.)

Original support done by Sudhakar Rajashekhara.
Signed-off-by: NSudhakar Rajashekhara <sudhakar.raj@ti.com>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>

In addition, add board support for the DM355 Evaluation Module (EVM)
and the DM355 Leopard board.

Original DM355 EVM support done by Sandeep Paulraj, with significant
updates and improvements by David Brownell.  DM355 Leopord support
done by Koen Kooi.
Signed-off-by: NSandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: NKoen Kooi <koen@beagleboard.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>