anv: Set Stateless Data Port Access MOCS

This is the MOCS setting used for the A64 stateless messages which we
sometimes use for SSBO operations.

Fixes: 48ed2a7b "anv: Implement VK_EXT_buffer_device_address"
Fixes: 79fb0d27 "anv: Implement SSBOs bindings with GPU addr..."
Reviewed-by: Chad Versace <chadversary@chromium.org>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
(cherry picked from commit 6a2ff217)