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/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3c14240..9efe117 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2936,6 +2936,8 @@
 
 		lvds = I915_READ(lvds_reg);
 		lvds |= LVDS_PORT_EN | LVDS_A0A2_CLKA_POWER_UP | LVDS_PIPEB_SELECT;
+		/* set the corresponsding LVDS_BORDER bit */
+		lvds |= dev_priv->lvds_border_bits;
 		/* Set the B0-B3 data pairs corresponding to whether we're going to
 		 * set the DPLLs for dual-channel mode or not.
 		 */