Changing the arch/arm/dts/am335x-phytec-phycore.dts would be
another option but that would break loading a mainline kernel.
The idea/patch is coming from Jan.
This adds a devicetree-only driver for to configure the gpmc and its
child devices from dt. Currently only NAND is supported.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>