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