OMAPDSS: DISPC: pass pclk & lclk to check_horiz_timing_omap3

In order to make the scaling calculations independent of the current
hardware configuration (e.g. which manager is connected to this output),
we need to change the calc funcs to get all the variables needed for the
calculations via parameters.

This patch changes check_horiz_timing_omap3() to get pclk and lclk as
parameters.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>