Revert commit b6cf400aa fro llvm git (by Nemanja Ivanovic):

Fix bots after a9ad65a2b34f

  In the last commit, I neglected to initialize the new subtarget
  feature I added which caused failures on a few bots. This should fix
  that.

This unbreaks the build after r359981, which reverted upstream commit
a9ad65a2b34f.

Reported by:	jhibbits (and jenkins :)
MFC after:	6 weeks
X-MFC-With:	358851

contrib/llvm-project/llvm/lib/Target/PowerPC/PPCSubtarget.cpp

@@ -100,7 +100,6 @@ void PPCSubtarget::initializeEnvironment() {
   IsPPC6xx = false;
   IsE500 = false;
   FeatureMFTB = false;
-  AllowsUnalignedFPAccess = false;
   DeprecatedDST = false;
   HasLazyResolverStubs = false;
   HasICBT = false;