Few benchmarks still used libdrm so let's rewrite them to be libdrm
free. I tried to mimic the libdrm behavior as much as possible but
according how libdrm caches handles/mappings there may be some
differences in performance execution.

v2: Move benchmarks to scope without libdrm in meson.build

Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski@intel.com>
Cc: Petri Latvala <petri.latvala@intel.com>
Acked-by: Petri Latvala <petri.latvala@intel.com>