driver/ifc:Change accessor function to take care of endianness

IFC registers can be of type Little Endian or big Endian depending upon
Freescale SoC. Here SoC defines the register type of IFC IP.

So update acessor functions with common IFC acessor functions to take care
both type of endianness.

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Acked-by: York Sun <yorksun@freescale.com>