[Intel-gfx] [PATCH] drm/locking: Allow NULL crtc in

[shuang.he at intel.com]

Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                                  367/367              367/367
ILK                                  373/375              373/375
SNB                                  450/450              450/450
IVB                 -2              502/503              500/503
BYT                                  289/289              289/289
HSW                 -3              567/567              564/567
BDW                                  417/417              417/417
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
IVB  igt_gem_bad_reloc_negative-reloc-lut      NSPT(3, M21M34M4)PASS(1, M21)      NSPT(1, M21)
IVB  igt_kms_fence_pin_leak      PASS(2, M21)      DMESG_WARN(1, M21)
HSW  igt_gem_bad_reloc_negative-reloc-lut      NSPT(10, M40M20)PASS(1, M20)      NSPT(1, M40)
HSW  igt_kms_rotation_crc_primary-rotation      PASS(11, M20M40)      DMESG_WARN(1, M40)
HSW  igt_pm_rc6_residency_rc6-accuracy      PASS(11, M20M40)      FAIL(1, M40)