When we first started using genxml, we decided to represent MOCS as an
actual structure, and pack values.  However, in many places, it was more
convenient to use a numeric value rather than treating it as a struct,
so we added secondary setters in a bunch of places as well.

We were not entirely consistent, either.  Some places only had one.
Gen6 had both kinds of setters for STATE_BASE_ADDRESS, but newer gens
only had the struct-based setters.  The names were sometimes "Constant
Buffer Object Control State" instead of "Memory", making it harder to
find.  Many had prefixes like "Vertex Buffer MOCS"...in a vertex buffer
packet...which is a bit redundant.

On modern hardware, MOCS is simply an index into a table, but we were
still carrying around the structure with an "Index to MOCS Table" field,
in addition to the direct numeric setters.  This is clunky - we really
just want a number on new hardware.

This patch eliminates the struct-based setters, and makes the numeric
setters be consistently called "MOCS".  We leave the struct definition
around on Gen7-8 for reference purposes, but it is unused.

v2: Drop bonus "Depth Buffer MOCS" fields on Gen7.5 and Gen9

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>