OMAP3 SDRC: Move the clk stabilization delay to the right place

The clock stabilization delay post a M2 divider change is needed
even before a SDRC interface clock re-enable and not only before
jumping back to SDRAM.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>