OMAPDSS: DISPC: Correct DISPC functional clock usage

DISPC_FCLK is incorrectly used as functional clock of DISPC in scaling
calculations. So, DISPC_CORE_CLK replaces as functional clock of DISPC.
DISPC_CORE_CLK is derived from DISPC_FCLK divided by an independent DISPC
divisor LCD.

Signed-off-by: Chandrabhanu Mahapatra <cmahapatra@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/dss.h b/drivers/video/omap2/dss/dss.h
index 1dc336b..5ca67f1 100644
--- a/drivers/video/omap2/dss/dss.h
+++ b/drivers/video/omap2/dss/dss.h
@@ -448,6 +448,7 @@
 		enum omap_panel_config config, u8 acbi, u8 acb);
 unsigned long dispc_mgr_lclk_rate(enum omap_channel channel);
 unsigned long dispc_mgr_pclk_rate(enum omap_channel channel);
+unsigned long dispc_core_clk_rate(void);
 int dispc_mgr_set_clock_div(enum omap_channel channel,
 		struct dispc_clock_info *cinfo);
 int dispc_mgr_get_clock_div(enum omap_channel channel,