Pffft (#3780)

* Adding a dep on pffft

* Adding submodule (somehow disappeared in previous commit)

* Added WORKSPACE and modified .gitmodules

* Formatted WORKSPACE

* Fixed files referencing incorrect path

* emoved more incorrect deps
diff --git a/.gitmodules b/.gitmodules
index c486be1..45076ab 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -53,6 +53,9 @@
 [submodule "third_party/cpuinfo"]
 	path = third_party/cpuinfo
 	url = https://github.com/pytorch/cpuinfo.git
+[submodule "third_party/pffft"]
+	path = third_party/pffft
+	url = https://bitbucket.org/jpommier/pffft.git
 [submodule "third_party/llvm-bazel"]
 	path = third_party/llvm-bazel
 	url = https://github.com/google/llvm-bazel.git