ddr: altera: sequencer: Pluck out RW_MGR_* macros from code

Actually convert the sequencer code to use socfpga_sdram_rw_mgr_config
instead of the RW_MGR_* macros. This is just an sed exercise here, no
manual coding needed.

Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Dinh Nguyen <dinguyen@opensource.altera.com>