video: fbdev: omapfb: acx565akm: replace snprintf with sysfs_emit

coccinelle report:
./drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c:
479:9-17: WARNING: use scnprintf or sprintf

Use sysfs_emit instead of scnprintf or sprintf makes more sense.
Reported-by: NZeal Robot <zealci@zte.com.cn>
Signed-off-by: NYang Guang <yang.guang5@zte.com.cn>
Signed-off-by: NHelge Deller <deller@gmx.de>

drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c

@@ -476,7 +476,7 @@ static ssize_t show_cabc_available_modes(struct device *dev,
 	int i;
 
 	if (!ddata->has_cabc)
-		return snprintf(buf, PAGE_SIZE, "%s\n", cabc_modes[0]);
+		return sysfs_emit(buf, "%s\n", cabc_modes[0]);
 
 	for (i = 0, len = 0;
 	     len < PAGE_SIZE && i < ARRAY_SIZE(cabc_modes); i++)