intel: Stop redirecting state cache to command streamer cache section

intel: Stop redirecting state cache to command streamer cache section

This bit redirects the state cache from the unified/RO sections of the
L3 cache to the "CS command buffer" section of the cache, which would
be set up via TCCNTLREG.  The documentation says:

   "Additionaly, this redirection should be enabled only if there is a
    non-zero allocation for the CS command buffer section."

We don't allocate any cache to the CS command buffer section, so
enabling this redirection effectively disabled the state cache.
The Windows driver only sets up that section when using POSH, which
we do not currently use.  So, leave it unallocated and disable the
redirection to get a functional state cache again.

Improves performance in Civilization VI by 18%, Manhattan 3.0 by 6%,
and Car Chase by 2%.