Shrink a couple of hs-boot files

IfaceType.hs-boot and ToIface.hs-boot were bigger than they
needed to be, so I'm shrinking them.

compiler/iface/IfaceType.hs-boot

--- Exists to allow TyCoRep to import pretty-printers
-module IfaceType where
+-- Used only by ToIface.hs-boot
+
+module IfaceType( IfaceType, IfaceTyCon, IfaceForAllBndr
+                , IfaceCoercion, IfaceTyLit, IfaceTcArgs ) where
 
 import Var (TyVarBndr, ArgFlag)
 import TyCon (TyConBndrVis)
-import BasicTypes (TyPrec)
-import Outputable (Outputable, SDoc)
 import FastString (FastString)
 
+data IfaceTcArgs
 type IfLclName = FastString
 type IfaceKind = IfaceType
-type IfacePredType = IfaceType
 
-data ShowForAllFlag
 data IfaceType
 data IfaceTyCon
 data IfaceTyLit
 data IfaceCoercion
-data IfaceTcArgs
-type IfaceTvBndr = (IfLclName, IfaceKind)
+type IfaceTvBndr      = (IfLclName, IfaceKind)
 type IfaceTyConBinder = TyVarBndr IfaceTvBndr TyConBndrVis
 type IfaceForAllBndr  = TyVarBndr IfaceTvBndr ArgFlag
-
-instance Outputable IfaceType
-
-pprIfaceType, pprParendIfaceType :: IfaceType -> SDoc
-pprIfaceSigmaType :: ShowForAllFlag -> IfaceType -> SDoc
-pprIfaceTyLit :: IfaceTyLit -> SDoc
-pprIfaceForAll :: [IfaceForAllBndr] -> SDoc
-pprIfaceTvBndr :: Bool -> IfaceTvBndr -> SDoc
-pprUserIfaceForAll :: [IfaceForAllBndr] -> SDoc
-pprIfaceContext :: [IfacePredType] -> SDoc
-pprIfaceContextArr :: [IfacePredType] -> SDoc
-pprIfaceTypeApp :: TyPrec -> IfaceTyCon -> IfaceTcArgs -> SDoc
-pprIfaceCoTcApp :: TyPrec -> IfaceTyCon -> [IfaceCoercion] -> SDoc
-pprTyTcApp :: TyPrec -> IfaceTyCon -> IfaceTcArgs -> SDoc
-pprIfacePrefixApp :: TyPrec -> SDoc -> [SDoc] -> SDoc

compiler/iface/ToIface.hs-boot

 module ToIface where
 
 import {-# SOURCE #-} TyCoRep
-import {-# SOURCE #-} IfaceType
+import {-# SOURCE #-} IfaceType( IfaceType, IfaceTyCon, IfaceForAllBndr
+                               , IfaceCoercion, IfaceTyLit, IfaceTcArgs )
 import Var ( TyVar, TyVarBinder )
 import TyCon ( TyCon )
 import VarSet( VarSet )
 
 -- For TyCoRep
-toIfaceType :: Type -> IfaceType
 toIfaceTypeX :: VarSet -> Type -> IfaceType
 toIfaceTyLit :: TyLit -> IfaceTyLit
 toIfaceForAllBndr :: TyVarBinder -> IfaceForAllBndr
-toIfaceTvBndr :: TyVar -> IfaceTvBndr
 toIfaceTyCon :: TyCon -> IfaceTyCon
 toIfaceTcArgs :: TyCon -> [Type] -> IfaceTcArgs
 toIfaceCoercion :: Coercion -> IfaceCoercion