[AMDGPU] Delete amdgpu-unify-metadata in optdriver.cpp (#153717)

Fix up for #153548, which is
from #153150.

Author: Shoreshen

llvm/tools/opt/optdriver.cpp

@@ -340,7 +340,6 @@ static bool shouldPinPassToLegacyPM(StringRef Pass) {
       "amdgpu-lower-kernel-attributes",
       "amdgpu-propagate-attributes-early",
       "amdgpu-propagate-attributes-late",
-      "amdgpu-unify-metadata",
       "amdgpu-printf-runtime-binding",
       "amdgpu-always-inline"};
   if (llvm::is_contained(PassNameExactToIgnore, Pass))