[Intel-gfx] [PATCH 2/2] drm/i915: always preserve bios swizzling

[shuang.he at intel.com]

Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
Task id: 6060
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                 -2              270/270              268/270
ILK                                  301/301              301/301
SNB                                  304/304              304/304
IVB                                  338/338              338/338
BYT                                  287/287              287/287
HSW                                  361/361              361/361
BDW                                  309/309              309/309
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
 PNV  igt at gen3_render_linear_blits      FAIL(1)PASS(1)      FAIL(2)
*PNV  igt at gem_fd_exhaustion      PASS(2)      NO_RESULT(1)PASS(1)
Note: You need to pay more attention to line start with '*'