davinci: enable forced transitions on PSC

Some DaVinci modules like the SATA on DA850
need forced module state transitions.

Define a "force" flag which can be passed to
the PSC config function to enable it to make
forced transitions.

Forced transitions shouldn't normally be attempted,
unless the TRM explicitly specifies its usage.

ChangeLog:
v2:
Modified to take care of the fact that
davinci_psc_config() now takes the flags
directly.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>