i965: Disable internal CCS for shadows of multi-sampled windows

i965: Disable internal CCS for shadows of multi-sampled windows

If window system supports Y-tiling but not CCS_E, we currently create an
internal CCS for any window system buffers and then resolve right before
handing it off to X or Wayland.  In the case of the single-sampled
shadow of a multi-sampled window system buffer, this is pointless
because the only thing we do with it is use it as a MSAA resolve target
so we do MSAA resolve -> CCS resolve -> hand to the window system.
Instead, just disable CCS for the shadow and then the MSAA resolve will
write uncompressed directly into it.  If the window system supports
CCS_E, we will still use CCS_E, we just won't do internal CCS.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>