powerpc/fsl: Add support for Integrated Flash Controller

Integrated Flash Controller supports various flashes like NOR, NAND
and other devices using NOR, NAND and GPCM Machine available on it.
IFC supports four chip selects.

Signed-off-by: Dipen Dudhat <Dipen.Dudhat@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Liu Shuo <b35362@freescale.com>
Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>