drm/i915: Set the LVDS_BORDER when using LVDS scaling mode

According to the spec the LVDS_BORDER_ENABLE bit decides whether the border
data should be included in the active display and data sent to the panel.
Border should be used when in VGA centered (un-scaled) mode or when scaling
a 4:3 source image to a wide screen panel (typical 16:9).

So when the LVDS scaling is used, decide whether the LVDS_BORDER should be
enabled or not according to the current scaling mode.

At the same time fix the typo error in LVDS center scaling mode.

https://bugs.freedesktop.org/show_bug.cgi?id=23789

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
tested-by: Zhao Jian <jian.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 0466ddb..5f92724 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -968,6 +968,8 @@
 #define   LVDS_PORT_EN			(1 << 31)
 /* Selects pipe B for LVDS data.  Must be set on pre-965. */
 #define   LVDS_PIPEB_SELECT		(1 << 30)
+/* Enable border for unscaled (or aspect-scaled) display */
+#define   LVDS_BORDER_ENABLE		(1 << 15)
 /*
  * Enables the A0-A2 data pairs and CLKA, containing 18 bits of color data per
  * pixel.