Add LANGUAGE BangPatterns to modules that use bang patterns

GHC/Integer.lhs

 \begin{code}
+{-# LANGUAGE BangPatterns #-}
 {-# OPTIONS_GHC -XNoImplicitPrelude #-}
 {-# OPTIONS_HADDOCK hide #-}
 -----------------------------------------------------------------------------

GHC/Integer/GMP/Internals.hs

 {-# LANGUAGE ForeignFunctionInterface, GHCForeignImportPrim,
-             MagicHash, UnboxedTuples, UnliftedFFITypes #-}
+             MagicHash, UnboxedTuples, UnliftedFFITypes, BangPatterns #-}
 {-# OPTIONS_GHC -XNoImplicitPrelude #-}
 {-# OPTIONS_HADDOCK hide #-}