am33xx: Make config_cmd_ctrl / config_ddr_data take const structs

Rework the EMIF4/DDR code slightly to setup the structs that
config_cmd_ctrl and config_ddr_data take to be setup at compile time and
mark them as const.  This lets us simplify the calling path slightly as
well as making it easier to deal with DDR3.

Signed-off-by: Tom Rini <trini@ti.com>
3 files changed