i965: Extract tiling from fast clear decision

i965: Extract tiling from fast clear decision

There are several constraints when determining if one can fast clear a surface.
Some of these are alignment, pixel density, tiling formats, and others that vary
by generation. The helper function which exists today does a suitable job,
however it conflates "BO properties" with "Miptree properties" when using
tiling. I consider the former to be attributes of the physical surface, things
which are determined through BO allocation, and the latter being attributes
which are derived from the API, and having nothing to do with the underlying
surface.

Determining tiling properties and creating miptrees are related operations
(when we allocate a BO for a miptree) with some disjoint constraints. By
extracting the decisions into two distinct choices (tiling vs. miptree
properties), we gain flexibility throughout the code to make determinations
about when we can or cannot fast clear strictly on the miptree.

To signify this change, I've also renamed the function to indicate it is a
distinction made on the miptree. I am torn as to whether or not it was a good
idea to remove "non_msrt" since it's a really nice thing for grep.

v2:
Reword some comments (Chad)
intel_is_non_msrt_mcs_tile_supported->intel_tiling_supports_non_msrt_mcs (Chad)
Make full if ladder for gens in above function (Chad)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Cc: Topi Pohjolainen <topi.pohjolainen@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Chad Versace <chad.versace@linux.intel.com>