video: fbdev: omap2: omapfb: displays: panel-dsi-cm: Use time comparison kernel macro.

Use time_before_eq() kernel macro for time comparison.

Signed-off-by: Karim Eshapa <karim.eshapa@gmail.com>
Cc: tomi.valkeinen@ti.com
Cc: peter.ujfalusi@ti.com
Cc: tj@kernel.org
Cc: mingo@kernel.org
[b.zolnierkie: patch description fixup]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>