ARM: DRA72x: DDR3: Fix EMIF timings for 666MHz clock

DDR3 timing and latency paramenters were not configured
correctly for 666MHz. Fixing the timing and latency values
according to Data sheet.
This fixes the random crashes seen on DRA72-evm.

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