Revert part of d257e57. (llvm#2654)

The changes introduced in the d257e57 caused a regression on gfx1100 at -O0. The compilation of all code containing OpenMP target construct was failing. Please see further details in
llvm#2499.

The author of the commit @guochen2_amdeng has asked me to revert this part of the commit to fix the regression.

Author: abidh

llvm/lib/Target/AMDGPU/AMDGPU.td

@@ -1800,8 +1800,7 @@ def FeatureISAVersion11_0_Common : FeatureSet<
     [FeatureMSAALoadDstSelBug,
      FeatureVALUTransUseHazard,
      FeatureMADIntraFwdBug,
-     FeaturePrivEnabledTrap2NopBug,
-     FeatureRealTrue16Insts])>;
+     FeaturePrivEnabledTrap2NopBug])>;
 
 def FeatureISAVersion11_0_0 : FeatureSet<
   !listconcat(FeatureISAVersion11_0_Common.Features,