OMAP: DSS2: move get_recommended_bpp()

Move get_recommended_bpp() from omap_dss_device to omap_dss_driver.

This is part of a larger patch-set, which moves the control from omapdss
driver to the display driver.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
diff --git a/drivers/video/omap2/displays/panel-taal.c b/drivers/video/omap2/displays/panel-taal.c
index 11d69b6..e00502e 100644
--- a/drivers/video/omap2/displays/panel-taal.c
+++ b/drivers/video/omap2/displays/panel-taal.c
@@ -990,6 +990,8 @@
 
 	.setup_update	= taal_setup_update,
 	.get_resolution	= taal_get_resolution,
+	.get_recommended_bpp = omapdss_default_get_recommended_bpp,
+
 	.enable_te	= taal_enable_te,
 	.wait_for_te	= taal_wait_te,
 	.set_rotate	= taal_rotate,