[commit: ghc] master: Bump mtl submodule to v2.2.2 (c67cf9e)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/c67cf9e9e66f629440c80ae3bf1616e2aac7002b/ghc

>---------------------------------------------------------------

commit c67cf9e9e66f629440c80ae3bf1616e2aac7002b
Author: Ben Gamari <ben at smart-cactus.org>
Date:   Sat Jul 14 11:33:13 2018 -0400

    Bump mtl submodule to v2.2.2


>---------------------------------------------------------------

c67cf9e9e66f629440c80ae3bf1616e2aac7002b
 libraries/mtl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libraries/mtl b/libraries/mtl
index bf4af11..c7d3967 160000
--- a/libraries/mtl
+++ b/libraries/mtl
@@ -1 +1 @@
-Subproject commit bf4af114ba3d35b2937fc74926aa49e128dd6c1f
+Subproject commit c7d396732bd45e409478bd4df1d0ca95d6f39356