OMAPFB: remove silly loop in fb2display()

fb2display() has a for loop which always returns at the first iteration.
Replace the loop with a simple if.

This removes the smatch warning:

drivers/video/omap2/omapfb/omapfb.h:153 fb2display() info: loop could be
replaced with if statement.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/omap2/omapfb/omapfb.h

@@ -144,16 +144,16 @@ int omapfb_set_update_mode(struct fb_info *fbi, enum omapfb_update_mode mode);
 static inline struct omap_dss_device *fb2display(struct fb_info *fbi)
 {
 	struct omapfb_info *ofbi = FB2OFB(fbi);
-	int i;
+	struct omap_overlay *ovl;
 
 	/* XXX: returns the display connected to first attached overlay */
-	for (i = 0; i < ofbi->num_overlays; i++) {
-		struct omap_overlay *ovl = ofbi->overlays[i];
 
-		return ovl->get_device(ovl);
-	}
+	if (ofbi->num_overlays == 0)
+		return NULL;
 
-	return NULL;
+	ovl = ofbi->overlays[0];
+
+	return ovl->get_device(ovl);
 }
 
 static inline struct omapfb_display_data *get_display_data(