Enabling or disabling a PSC can take certain
modifiers like "disable with reset", "force
enable/disable" and "enable/disable with local
reset" apart from the regular clock gating
functionality.

Pass a flags argument to davinci_psc_config()
so these variations can be supported there.

At this time only "disable with reset" is
supported, but other functionality will be
added in subsequent patches.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>