drm: Add 800x600 (SVGA) screen resolution to the built-in EDIDs

The 800x600 (SVGA) screen resolution was lacking in the set of
built-in selectable EDID screen resolutions that can be used to
repair misbehaving monitor firmware.

This patch adds the related data set and expands the documentation.
Note that the SVGA bit occupies a different byte to all the existing
users of the established timing bits forcing a rework of the
ESTABLISHED_TIMINGS_BITS macro.

Tested new EDID on an aged (and misbehaving) industrial LCD panel;
existing EDIDs still pass edid-decode's checksum checks.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Carsten Emde <C.Emde@osadl.org>
Cc: linux-doc@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/Documentation/EDID/1600x1200.S b/Documentation/EDID/1600x1200.S
index 0ded64c..a45101c 100644
--- a/Documentation/EDID/1600x1200.S
+++ b/Documentation/EDID/1600x1200.S
@@ -36,7 +36,7 @@
 #define DPI 72
 #define VFREQ 60 /* Hz */
 #define TIMING_NAME "Linux UXGA"
-#define ESTABLISHED_TIMINGS_BITS 0x00 /* none */
+/* No ESTABLISHED_TIMINGx_BITS */
 #define HSYNC_POL 1
 #define VSYNC_POL 1
 #define CRC 0x9d