Remove SDMAConcurrentCopies from gfx906 execution

This is intermittently causing VM faults and excessive evictions, which
causes the rest of the tests to fail. Take it out for now until someone
can investigate

Change-Id: I9c43890bc9f03a4a31efbc18df0df5e40a232c58


[ROCm/ROCR-Runtime commit: 381dba3932]

projects/rocr-runtime/tests/kfdtest/scripts/kfdtest.exclude

@@ -134,6 +134,7 @@ VEGA20_TESTS_BLACKLIST=\
 "KFDExceptionTest.InvalidWriteAddress:"\
 "KFDQMTest.CreateQueueStressSingleThreaded:"\
 "KFDQMTest.GPUDoorbellWrite:"\
+"KFDQMTest.SdmaConcurrentCopies:"\
 "KFDMemoryTest.MemoryRegister"
 
 RAVEN_TESTS_BLACKLIST=\