[Intel-gfx] [PATCH v3] drm/i915: Fix i915_dma_map_single positive error code

[shuang.he at intel.com]

Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he at intel.com)
Task id: 6041
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                 -1              269/269              268/269
ILK                                  303/303              303/303
SNB                                  304/304              304/304
IVB                 -1              338/338              337/338
BYT                                  287/287              287/287
HSW                                  362/362              362/362
BDW                                  310/310              310/310
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
 PNV  igt at gen3_render_linear_blits      FAIL(1)PASS(2)      FAIL(2)
*IVB  igt at gem_storedw_batches_loop@normal      PASS(2)      DMESG_WARN(1)PASS(1)
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