Updated submodule path, commit, and updated readme

.gitmodules

 [submodule "hpvm/projects/predtuner"]
 	path = hpvm/projects/predtuner
-	url = git@gitlab.engr.illinois.edu:yifanz16/predtuner.git
+	url = ../predtuner.git
+	branch = hpvm

README.md

@@ -68,6 +68,7 @@ Checkout HPVM and go to directory `./hpvm` under project root:
 git clone --recursive https://gitlab.engr.illinois.edu/llvm/hpvm.git
 cd hpvm/
 git checkout approx_hpvm_reorg_keras
+git submodule update --init --recursive
 cd hpvm/
 ```
 

predtuner @ 70ead4a7

-Subproject commit cef07897325f0427246a1f2d71fbf9562656465f
+Subproject commit 70ead4a70536ec7af29a99658a9e207b6e16d230