i965: Rename MIPTREE_LAYOUT_ALLOC_* -> MIPTREE_LAYOUT_TILING_*.

i965: Rename MIPTREE_LAYOUT_ALLOC_* -> MIPTREE_LAYOUT_TILING_*.

Ben suggested that I rename MIPTREE_LAYOUT_ALLOC_ANY_TILED since it
needed to include no tiling at all, but the name
MIPTREE_LAYOUT_ALLOC_ANY is pretty nondescriptive. We can avoid
confusion by replacing "ALLOC" with "TILING" in the identifiers.

Reviewed-by: Ben Widawsky <ben@bwidawsk.net>