uboot-phytec

ARM: AM43xx: Enable DDR dynamic IO power down for DDR3

This patch enables dynamically powering down the
IO receiver when not performing a read on DDR3 board.
This optimizes both active and standby power consumption.
This is derived from a patch that is done on AM335x[1]

[1] http://arago-project.org/git/projects/?p=u-boot-am33x.git;a=commit;h=6a9ee4bc72ece53fabf01825605fba3d71d5feb2

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>