bus: Add omap gpmc driver ...

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>

bus: Add imx-weim support ...

Mostly taken from the kernel with support for other SoCs from
Alexander Shiyan.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Alexander Shiyan <shc_work@mail.ru>