Add mmu memmap, some memory regions are reserved by M4, Arm Trusted Firmware, so need to get memreg using SCFW API and setup the memmap. Add dram_init, dram_init_banksize, get_effective_memsize functions, according to the memreg. Signed-off-by: Peng Fan <peng.fan@nxp.com> Reviewed-by: Anatolij Gustschin <agust@denx.de> Cc: Stefano Babic <sbabic@denx.de>