Staging: asus_oled: fix image processing

Programming an image was broken, because odev->buf_offs was not advanced
for val == 0 in append_values(). This regression was introduced in:

 commit 1ff12a4a
 Author: Kevin A. Granade <kevin.granade@gmail.com>
 Date:   Sat Sep 5 01:03:39 2009 -0500

     Staging: asus_oled: Cleaned up checkpatch issues.

Fix the image processing by special-casing val == 0.

I have tested this change on an Asus G50V laptop only.

Cc: Jakub Schmidtke <sjakub@gmail.com>
Cc: Kevin A. Granade <kevin.granade@gmail.com>
Signed-off-by: NPekka Paalanen <pq@iki.fi>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/asus_oled/asus_oled.c

@@ -355,7 +355,14 @@ static void send_data(struct asus_oled_dev *odev)
 
 static int append_values(struct asus_oled_dev *odev, uint8_t val, size_t count)
 {
-	while (count-- > 0 && val) {
+	odev->last_val = val;
+
+	if (val == 0) {
+		odev->buf_offs += count;
+		return 0;
+	}
+
+	while (count-- > 0) {
 		size_t x = odev->buf_offs % odev->width;
 		size_t y = odev->buf_offs / odev->width;
 		size_t i;
@@ -406,7 +413,6 @@ static int append_values(struct asus_oled_dev *odev, uint8_t val, size_t count)
 			;
 		}
 
-		odev->last_val = val;
 		odev->buf_offs++;
 	}