OMAP4: EMIF: LPDDR interface configuration update

In latest TRMs for OMAP4 family LPDDR recommended
setting have been changed. This patch does
corresponding changes in the code.

Change-Id: Ibd81b8196db74df5a7c3e29788c72a7b3628a22c
Signed-off-by: Ruslan Bilovol <ruslan.bilovol@ti.com>
apply this to 4460