[Intel-gfx] [PATCH] drm/i915: Fix comments about CHV snoop behaviour

[shuang.he at intel.com]

Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
-------------------------------------Summary-------------------------------------
Platform: baseline_drm_intel_nightly_pass_rate->patch_applied_pass_rate
BYT: pass/total=290/291->290/291
PNV: pass/total=352/356->356/356
ILK: pass/total=371/372->371/372
IVB: pass/total=545/546->544/546
SNB: pass/total=424/425->424/425
HSW: pass/total=579/579->579/579
BDW: pass/total=434/435->434/435
-------------------------------------Detailed-------------------------------------
test_platform: test_suite, test_case, result_with_drm_intel_nightly(count, machine_id...)...->result_with_patch_applied(count, machine_id)...
PNV: Intel_gpu_tools, igt_gen3_mixed_blits, DMESG_WARN(1, M23) -> PASS(4, M23)
PNV: Intel_gpu_tools, igt_gen3_render_mixed_blits, CRASH(1, M23) -> PASS(1, M23)
PNV: Intel_gpu_tools, igt_gen3_render_tiledx_blits, CRASH(1, M23) -> PASS(1, M23)
PNV: Intel_gpu_tools, igt_gen3_render_tiledy_blits, CRASH(1, M23) -> PASS(1, M23)
IVB: Intel_gpu_tools, igt_kms_cursor_crc_cursor-128x128-random, PASS(1, M4) -> DMESG_WARN(1, M21)PASS(3, M21)