[Intel-gfx] [PATCH i-g-t v4] tests/pm_rpm tests for set_caching and set_tiling

[Marius Vlad]

v4: re-bind the gem objects each time before calling
disable_all_screens_and_wait().

v3: Use smaller sizes when allocating gem objects for caching tests.

v2: use mmap to gtt instead off cpu and various style-changes.

Reviewed-by: Imre Deak <imre.deak at intel.com>