ARM: DRA: EMIF: Change DDR3 settings to use hw leveling

Currently the DDR3 memory on DRA7 ES1.0 evm board is enabled using
software leveling. This was done since hardware leveling was not
working. Now that the right sequence to do hw leveling is identified,
use it. This is required for EMIF clockdomain to idle and come back
during lowpower usecases.

Signed-off-by: Sricharan R <r.sricharan@ti.com>