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

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=\