drm-tests: restore psr value at the end of tests on i915 platforms

If any feature is disabled intentionally, it should
be restored to its original state at the end of
testing so that the test doesn't affect general
usage. Otherwise, any tests conducted after this
test may produce false negatives.

BUG=None
TEST=Check /sys/module/i915/parameters/enable_psr
before and after running 'mmap_test' to ensure that
the value is the same in both cases.

Change-Id: If916e7f5d9ed5c12fc5d9b3b1ef1dd0fd4a6696d
Signed-off-by: Casey Bowman <casey.g.bowman@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/1246308
Commit-Ready: Casey G Bowman <casey.g.bowman@intel.com>
Tested-by: Edward Baker <edward.baker@intel.com>
Reviewed-by: Ilja H. Friedel <ihf@chromium.org>
1 file changed