powerpc:mpc85xx: Add ifc nand boot support for TPL/SPL

powerpc:mpc85xx: Add ifc nand boot support for TPL/SPL

Using the TPL method for nand boot by sram was already
supported. Here add some code for mpc85xx ifc nand boot.

	- For ifc, elbc, esdhc, espi, all need the SPL without
	section .resetvec.
	- Use a clear function name for nand spl boot.
	- Add CONFIG_SPL_DRIVERS_MISC_SUPPORT to compile the fsl_ifc.c
	in spl/Makefile;

Signed-off-by: Po Liu <[email protected]>
Acked-by: Scott Wood <[email protected]>
Reviewed-by: York Sun <[email protected]>