mtd: add GPMI-NAND driver in the config and Makefile

add the GPMI-NAND driver in the relevant Kconfig and Makefile in the MTD.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
Tested-by: Koen Beel <koen.beel@barco.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>