This renames the dcdofs config option in the imx-image tool to ivtofs.  dcdofs
is a misnomer. The DCD (Device Configuration Data) is only one part of the data
linked into the IVT (Image Vector Table), but the meaning of the option is
really the latter, not the former.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

The defines are also in mach/clocks-imx6.h prefixed
with MXC instead of MX6.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Now that the MAX variant of the board is also supported by the
same code, rename the board directory to the more generic nitrogen6.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>