This creates the TCL interface for configuring an AT91SAM9 NAND flash
controller and implements the necessary functions to correctly work with
a NAND flash device connected to the chip.  This includes updates to the
driver list and the Makefile.am to support building the driver and also
houses the documentation update in openocd.texi.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>