drm/intel: Fix initialization if startup happens in interlaced mode [v2]

My EFI BIOS starts the graphics card up in my projector's preferred EDID
mode, 1080@60i. The Intel driver does not clear all the interlaced bits.

This patch introduces a new PIPECONF_INTERLACE_MASK define and uses it
to restore progressive mode.

Signed-of-by: Christian Schmidt <schmidt@digadd.de>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/i915/i915_reg.h

@@ -2312,6 +2312,7 @@
 #define   PIPECONF_PROGRESSIVE	(0 << 21)
 #define   PIPECONF_INTERLACE_W_FIELD_INDICATION	(6 << 21)
 #define   PIPECONF_INTERLACE_FIELD_0_ONLY		(7 << 21)
+#define   PIPECONF_INTERLACE_MASK	(7 << 21)
 #define   PIPECONF_CXSR_DOWNCLOCK	(1<<16)
 #define   PIPECONF_BPP_MASK	(0x000000e0)
 #define   PIPECONF_BPP_8	(0<<5)

drivers/gpu/drm/i915/intel_display.c

@@ -5136,7 +5136,7 @@ static int i9xx_crtc_mode_set(struct drm_crtc *crtc,
 		adjusted_mode->crtc_vsync_end -= 1;
 		adjusted_mode->crtc_vsync_start -= 1;
 	} else
-		pipeconf &= ~PIPECONF_INTERLACE_W_FIELD_INDICATION; /* progressive */
+		pipeconf &= ~PIPECONF_INTERLACE_MASK; /* progressive */
 
 	I915_WRITE(HTOTAL(pipe),
 		   (adjusted_mode->crtc_hdisplay - 1) |