OMAP: DSS2: move get_resolution()

Move get_resolution() 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/omapfb/omapfb-ioctl.c b/drivers/video/omap2/omapfb/omapfb-ioctl.c
index 36afab3..6deabb9 100644
--- a/drivers/video/omap2/omapfb/omapfb-ioctl.c
+++ b/drivers/video/omap2/omapfb/omapfb-ioctl.c
@@ -167,7 +167,7 @@
 	if (w == 0 || h == 0)
 		return 0;
 
-	display->get_resolution(display, &dw, &dh);
+	display->driver->get_resolution(display, &dw, &dh);
 
 	if (x + w > dw || y + h > dh)
 		return -EINVAL;
@@ -752,7 +752,7 @@
 			break;
 		}
 
-		display->get_resolution(display, &xres, &yres);
+		display->driver->get_resolution(display, &xres, &yres);
 
 		p.display_info.xres = xres;
 		p.display_info.yres = yres;