powerpc/85xx: mpc8548cds - Add FPGA node to dts

Remove FPGA(CADMUS) macros in code. Move it to dts.

Signed-off-by: Zhao Chenhui <chenhui.zhao@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>