mx6sabresd: Use VESA 1024x768 timings

VESA 1024x768 results in much more accurate timings.

Based on the patch from Soeren Moch for the tbs2910 board.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
diff --git a/board/freescale/mx6sabresd/mx6sabresd.c b/board/freescale/mx6sabresd/mx6sabresd.c
index e9d9664..727334a 100644
--- a/board/freescale/mx6sabresd/mx6sabresd.c
+++ b/board/freescale/mx6sabresd/mx6sabresd.c
@@ -386,13 +386,13 @@
 		.refresh        = 60,
 		.xres           = 1024,
 		.yres           = 768,
-		.pixclock       = 15385,
-		.left_margin    = 220,
-		.right_margin   = 40,
-		.upper_margin   = 21,
-		.lower_margin   = 7,
-		.hsync_len      = 60,
-		.vsync_len      = 10,
+		.pixclock       = 15384,
+		.left_margin    = 160,
+		.right_margin   = 24,
+		.upper_margin   = 29,
+		.lower_margin   = 3,
+		.hsync_len      = 136,
+		.vsync_len      = 6,
 		.sync           = FB_SYNC_EXT,
 		.vmode          = FB_VMODE_NONINTERLACED
 } }, {
@@ -406,13 +406,13 @@
 		.refresh        = 60,
 		.xres           = 1024,
 		.yres           = 768,
-		.pixclock       = 15385,
-		.left_margin    = 220,
-		.right_margin   = 40,
-		.upper_margin   = 21,
-		.lower_margin   = 7,
-		.hsync_len      = 60,
-		.vsync_len      = 10,
+		.pixclock       = 15384,
+		.left_margin    = 160,
+		.right_margin   = 24,
+		.upper_margin   = 29,
+		.lower_margin   = 3,
+		.hsync_len      = 136,
+		.vsync_len      = 6,
 		.sync           = FB_SYNC_EXT,
 		.vmode          = FB_VMODE_NONINTERLACED
 } }, {