drm/i915: Add NV12 as supported format for primary plane

drm/i915: Add NV12 as supported format for primary plane

This patch adds NV12 to list of supported formats for
primary plane

v2: Rebased (Chandra Konduru)

v3: Rebased (me)

v4: Review comments by Ville addressed
Removed the skl_primary_formats_with_nv12 and
added NV12 case in existing skl_primary_formats

v5: Rebased (me)

v6: Missed the Tested-by/Reviewed-by in the previous series
Adding the same to commit message in this version.

v7: Review comments by Ville addressed
	Restricting the NV12 for BXT and on PIPE A and B
Rebased (me)

v8: Rebased (me)
Modified restricting the NV12 support for both BXT and KBL.

v9: Rebased (me)

v10: Addressed review comments from Maarten.
	Adding NV12 inside skl_primary_formats itself.

v11: Adding Reviewed By tag from Shashank Sharma

v12: Addressed review comments from Juha-Pekka Heikkila
"NV12 not to be supported by SKL"

v13: Addressed review comments from Ville
Added skl_pri_planar_formats to include NV12
and skl_plane_has_planar function to check for
NV12 support on plane. Added NV12 format to
skl_mod_supported. These were review comments
from Kristian Høgsberg <hoegsberg@gmail.com>

v14: Added reviewed by from Juha-Pekka Heikkila

v15: Rebased the series

v16: Added all tiling support under mod supported
for NV12. Credits to Megha Aggarwal

v17: Added RB by Maarten and Kristian

v18: Review comments from Maarten addressed -
Removing BROXTON support for NV12 due to WA826

v19: Addressed review comments from Maarten
Make changes to skl_mod_supported

Credits-to: Megha Aggarwal megha.aggarwal@intel.com
Credits-to: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Tested-by: Clinton Taylor <clinton.a.taylor@intel.com>
Reviewed-by: Kristian Høgsberg <hoegsberg@gmail.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: Clinton Taylor <clinton.a.taylor@intel.com>
Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Chandra Konduru <chandra.konduru@intel.com>
Signed-off-by: Nabendu Maiti <nabendu.bikash.maiti@intel.com>
Signed-off-by: Vidya Srinivas <vidya.srinivas@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1526074397-10457-6-git-send-email-vidya.srinivas@intel.com