intel/fs: restore message layout changes for cube array

intel/fs: restore message layout changes for cube array

This reverts commit bc04e2dacac that handled the change as a WA while
this is about a new feature, change done in message layout. Patch also
changes the original comment to not refer to Wa but bspec page.

Fixes: bc04e2dacac ("intel/fs: use generated helpers for Wa_1209978020 / Wa_18012201914")
Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Mark Janes <markjanes@swizzler.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22068>