[Intel-gfx] [PATCH] drm/i915: Remove locking for get-caching query

[shuang.he at intel.com]

Tested-By: Intel Graphics QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
Task id: 6343
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                 -1              199/199              198/199
ILK                                  302/302              302/302
SNB                                  316/316              316/316
IVB                                  342/342              342/342
BYT                                  286/286              286/286
BDW                                  321/321              321/321
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
*PNV  igt at gem_userptr_blits@forked-sync-swapping-interruptible      PASS(1)      INIT(1)
Note: You need to pay more attention to line start with '*'