ARM: config: keystone: enable AEMIF/NAND support

Keystone SoC uses the same NAND driver as Davinci, so enable
Davinci NAND and AEIMF that provides interface for it.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>