drm/i915: Add format modifiers for Intel

This was based on a patch originally by Kristian. It has been modified
pretty heavily to use the new callbacks from the previous patch.

v2:
  - Add LINEAR and Yf modifiers to list (Ville)
  - Combine i8xx and i965 into one list of formats (Ville)
  - Allow 1010102 formats for Y/Yf tiled (Ville)

v3:
  - Handle cursor formats (Ville)
  - Put handling for LINEAR in the mod_support functions (Ville)

v4:
  - List each modifier explicitly in supported modifiers (Ville)
  - Handle the CURSOR plane (Ville)

v5:
  - Split out cursor and sprite handling (Ville)

v6:
  - Actually use the sprite funcs (Emil)
  - Use unreachable (Emil)

v7:
  - Only allow Intel modifiers and LINEAR (Ben)

v8
  - Fix spite assert introduced in v6 (Daniel)

v9
  - Change vendor check logic to avoid magic 56 (Emil)
  - Reorder skl_mod_support (Ville)
  - make intel_plane_funcs static, could be done as of v5 (Ville)
  - rename local variable intel_format_modifiers to modifiers (Ville)
    - actually use sprite modifiers
  - split out modifier/formats by platform (Ville)

v10:
  - Undo vendor check from v9

v11:
  - Squash CCS advertisement into this patch (daniels)
  - Don't advertise CCS on higher sprite planes (daniels)

v12:
  - Don't advertise Y-tiled or CCS on any sprite planes, since we don't
    allocate enough DDB space for it to work. (daniels)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> (v8)
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Stone <daniels@collabora.com>