arm, davinci: add PLL0 prediv to da850 lowlevel setup

arm, davinci: add PLL0 prediv to da850 lowlevel setup

The OMAP-L138 has a pre-divider available on PLL0.

Add support to da850_lowlevel.c for configuring PLL0's pre-divider. This is
to achieve certain OPP's -- e.g. the 372MHz OPP used also by Linux.

Signed-off-by: Ben Gardiner <[email protected]>
Cc: Christian Riesch <[email protected]>
CC: Heiko Schocher <[email protected]>
Cc: Sandeep Paulraj <[email protected]>
Cc: Tom Rini <[email protected]>
Cc: Albert ARIBAUD <[email protected]>
Acked-by: Heiko Schocher <[email protected]>
Acked-by: Christian Riesch <[email protected]>