[Intel-gfx] [PATCH 2/2] drm/i915: Add runtime PM's usage_count in i915_runtime_pm_status

[shuang.he at intel.com]

Tested-By: Intel Graphics QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
Task id: 6540
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                 -1              270/270              269/270
ILK                                  303/303              303/303
SNB                                  312/312              312/312
IVB                                  343/343              343/343
BYT                                  287/287              287/287
BDW                                  318/318              318/318
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
*PNV  igt at gem_tiled_pread_pwrite      PASS(1)      FAIL(1)
Note: You need to pay more attention to line start with '*'