drm/i915: fix mode set on load pipe. (v2)

Booted my i965 machine and it started printing the unsupported pixel
format of 0 message (once I added content to it).

Oh looksie here, we pass 0. fix.

v2: compile it.

Buzilla: https://bugs.freedesktop.org/show_bug.cgi?id=45966Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDave Airlie <airlied@redhat.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

drivers/gpu/drm/i915/intel_display.c

@@ -6561,7 +6561,7 @@ intel_framebuffer_create_for_mode(struct drm_device *dev,
 	mode_cmd.height = mode->vdisplay;
 	mode_cmd.pitches[0] = intel_framebuffer_pitch_for_width(mode_cmd.width,
 								bpp);
-	mode_cmd.pixel_format = 0;
+	mode_cmd.pixel_format = drm_mode_legacy_fb_format(bpp, depth);
 
 	return intel_framebuffer_create(dev, &mode_cmd, obj);
 }