drm/fourcc: Document the Intel CCS modifiers' CC plane expected pitch

The driver expects the pitch of the Intel CCS CC color planes to be
64 bytes aligned, adjust the modifier descriptions accordingly.

Cc: Nanley Chery <nanley.g.chery@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Nanley Chery <nanley.g.chery@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220623144955.2486736-1-imre.deak@intel.com

include/uapi/drm/drm_fourcc.h

@@ -559,7 +559,7 @@ extern "C" {
  *
  * The main surface is Y-tiled and is at plane index 0 whereas CCS is linear
  * and at index 1. The clear color is stored at index 2, and the pitch should
- * be ignored. The clear color structure is 256 bits. The first 128 bits
+ * be 64 bytes aligned. The clear color structure is 256 bits. The first 128 bits
  * represents Raw Clear Color Red, Green, Blue and Alpha color each represented
  * by 32 bits. The raw clear color is consumed by the 3d engine and generates
  * the converted clear color of size 64 bits. The first 32 bits store the Lower
@@ -612,9 +612,9 @@ extern "C" {
  * outside of the GEM object in a reserved memory area dedicated for the
  * storage of the CCS data for all RC/RC_CC/MC compressible GEM objects. The
  * main surface pitch is required to be a multiple of four Tile 4 widths. The
- * clear color is stored at plane index 1 and the pitch should be ignored. The
- * format of the 256 bits of clear color data matches the one used for the
- * I915_FORMAT_MOD_Y_TILED_GEN12_RC_CCS_CC modifier, see its description
+ * clear color is stored at plane index 1 and the pitch should be 64 bytes
+ * aligned. The format of the 256 bits of clear color data matches the one used
+ * for the I915_FORMAT_MOD_Y_TILED_GEN12_RC_CCS_CC modifier, see its description
  * for details.
  */
 #define I915_FORMAT_MOD_4_TILED_DG2_RC_CCS_CC fourcc_mod_code(INTEL, 12)