drm/i915: Add CRTC output format YCBCR 4:4:4

This patch adds support for YCBCR 4:4:4 CRTC output format.
To do this, this patch extends the existing YCBCR 4:2:0
framework by:
- Adding new parameter in for YCBCR 4:4:4 enum crtc_iutput_format.
- Adding case for YCBCR 4:4:4 in while setting AVI infoframes.
- Adding necessary checks in modeset sequence.

V3: Added this patch in the series
V4: Added r-b from Maarten (for v3)
    Addressed review comment from Ville:
    Do not use (config->output_format > CRTC_OUTPUT_RGB)
V5: Rebase
V6: Rebase and small change, to accommodate changes in patch 2
V7: Fixed checkpatch alignment warnings
V8: Rebase
V9: Rebase
V10: Rebase
V11: Addressed review comment from Ville
     Missing output_format_str[INTEL_OUTPUT_FORMAT_YCBCR444]
     Added Ville's R-B.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1539325394-20788-3-git-send-email-shashank.sharma@intel.com
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 01530fa..3d23302 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -716,6 +716,7 @@ enum intel_output_format {
 	INTEL_OUTPUT_FORMAT_INVALID,
 	INTEL_OUTPUT_FORMAT_RGB,
 	INTEL_OUTPUT_FORMAT_YCBCR420,
+	INTEL_OUTPUT_FORMAT_YCBCR444,
 };
 
 struct intel_crtc_state {