powerpc: add CONFIG(s) require for using flash controller

Add CONFIG(s) required for NAND and NOR flash controller usage.
It defines MTD, Jffs2 and UBIFS file system required for controllers.

It also enables IFC controller

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>