drm/omap: encoder-tfp410: Don't fix timings in .set_timings() handler

Both the .check_timings() and .set_timings() handlers call
tfp410_fix_timings() to fix the timing's flags. As .check_timings() is
always called before .set_timings(), there's no need to fix the flags
twice. Remove the tfp410_fix_timings() call from .set_timings().

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>