drm/i915: Eliminate the horrendous format check code

drm/i915: Eliminate the horrendous format check code

Replace the messy framebuffer format/modifier validation code
with a single call to drm_any_plane_has_format(). The code was
extremely annoying to maintain as you had to have a lot of platform
checks for different formats. The new code requires zero maintenance.

v2: Nuke the modifier checks as well since the core does that too now
v3: Call drm_any_plane_has_format() from the driver code
v4: Rebase

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181029183453.28541-2-ville.syrjala@linux.intel.com
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>