[media] smiapp-pll: Add pixel rate in pixel array as output parameters

The actual pixel array pixel rate may be something else than vt_pix_clk_freq
on some implementations. Add a new field which contains the corrected value.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>