[Intel-gfx] [PATCH 5/5] drm/i915: Remove unneeded check on execlist ringbuf alloc

[shuang.he at intel.com]

Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
Task id: 5966
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                 -2              275/275              273/275
ILK                                  303/303              303/303
SNB                                  279/279              279/279
IVB                 -1              343/343              342/343
BYT                 -2              287/287              285/287
HSW                                  361/361              361/361
BDW                                  308/308              308/308
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
*PNV  igt_drv_debugfs_reader      PASS(3)      DMESG_WARN(1)PASS(1)
*PNV  igt_drv_hangman_error-state-sysfs-entry      PASS(3)      TIMEOUT(1)PASS(1)
*IVB  igt_gem_evict_everything_minor-normal      PASS(2)      DMESG_WARN(1)PASS(1)
*BYT  igt_kms_setmode_clone-exclusive-crtc      PASS(2)      DMESG_WARN(2)
*BYT  igt_kms_setmode_clone-single-crtc      PASS(2)      DMESG_WARN(2)
Note: You need to pay more attention to line start with '*'