intel: verify if hardware has LLC support

intel: verify if hardware has LLC support

Rely on libdrm HAS_LLC parameter to verify if hardware supports it. In
case the libdrm version does not supports this check, fallback to older
way of detecting it which assumed that GPUs newer than GEN6 have it.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>