hadrian: AArch64 supports the GHCi interpreter and SMP

I'm not sure how this was omitted from the list of supported
architectures.

hadrian/src/Oracles/Flag.hs

@@ -64,7 +64,7 @@ targetSupportsSMP :: Action Bool
 targetSupportsSMP = do
   unreg <- flag GhcUnregisterised
   armVer <- targetArmVersion
-  goodArch <- anyTargetArch ["i386", "x86_64", "sparc", "powerpc", "arm", "s390x"]
+  goodArch <- anyTargetArch ["i386", "x86_64", "sparc", "powerpc", "arm", "aarch64", "s390x"]
   if   -- The THREADED_RTS requires `BaseReg` to be in a register and the
        -- Unregisterised mode doesn't allow that.
      | unreg                -> return False

hadrian/src/Oracles/Setting.hs

@@ -242,7 +242,7 @@ ghcWithInterpreter = do
                           , "freebsd", "dragonfly", "netbsd", "openbsd"
                           , "darwin", "kfreebsdgnu" ]
     goodArch <- anyTargetArch [ "i386", "x86_64", "powerpc", "sparc"
-                              , "sparc64", "arm", "s390x" ]
+                              , "sparc64", "arm", "aarch64", "s390x" ]
     return $ goodOs && goodArch
 
 -- | Check to use @libffi@ for adjustors.