OMAP3: DMA: Enable idlemodes for DMA OCP

This patch enables MStandby smart-idle mode, autoidle smartidle mode,
and the autoidle bit for DMA4_OCP_SYSCONFIG.

Signed-off-by: Kalle Jokiniemi <ext-kalle.jokiniemi@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kevin Hilman <khilman@ti.deeprootsystems.com>