phy: dphy: Change units of wakeup and init parameters

The Init and wakeup D-PHY parameters are in the micro/milliseconds range,
putting the values real close to the types limits if they were in
picoseconds.

Move them to microseconds which should be better fit.

Suggested-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>