platform/x86: silead_dmi: Fix GP-electronic T701 entry

The GP-electronic T701 has its LCD panel mounted upside-down, initially
my plan was to fix this by transparently rotating the image in the i915
driver (my "drm/i915: Deal with upside-down mounted LCD" patch), but
that approach has been rejected instead the kernel will now export
a "panel orientation" property on the drm-connector for the panel and
let userspace deal with it.

But userspace expects the touchscreen coordinates to match the panel
coordinates *before* applying any rotation, so now that we no longer hide
the upside-down-ness of the LCD panel from userspace the coordinates being
generated are wrong and we need to apply a rotation of 180 degrees to the
coordinates to fix this.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/silead_dmi.c

@@ -83,6 +83,8 @@ static const struct silead_ts_dmi_data surftab_wintron70_st70416_6_data = {
 static const struct property_entry gp_electronic_t701_props[] = {
 	PROPERTY_ENTRY_U32("touchscreen-size-x", 960),
 	PROPERTY_ENTRY_U32("touchscreen-size-y", 640),
+	PROPERTY_ENTRY_BOOL("touchscreen-inverted-x"),
+	PROPERTY_ENTRY_BOOL("touchscreen-inverted-y"),
 	PROPERTY_ENTRY_STRING("firmware-name",
 			      "gsl1680-gp-electronic-t701.fw"),
 	{ }