Revert "[OpenMP] Default to single SDMA engine" (llvm#1096)

Author: ronlieb

offload/plugins-nextgen/amdgpu/src/rtl.cpp

@@ -2676,7 +2676,7 @@ struct AMDGPUDeviceTy : public GenericDeviceTy, AMDGenericDeviceTy {
         OMPX_StreamBusyWait("LIBOMPTARGET_AMDGPU_STREAM_BUSYWAIT", 2000000),
         OMPX_UseMultipleSdmaEngines(
             // setting default to true here appears to solve random sdma problem
-            "LIBOMPTARGET_AMDGPU_USE_MULTIPLE_SDMA_ENGINES", false),
+            "LIBOMPTARGET_AMDGPU_USE_MULTIPLE_SDMA_ENGINES", true),
         OMPX_ApuMaps("OMPX_APU_MAPS", false),
         OMPX_EnableGFX90ACoarseGrainUsmMaps(
             "OMPX_ENABLE_GFX90A_COARSE_GRAIN_USM_MAPS", false),