Add regtools binaries to gitignore

Change-Id: I5d65e6680329311916a3d890c81f3c39e9b655c4
diff --git a/.gitignore b/.gitignore
index 4233db9..a3ce328 100644
--- a/.gitignore
+++ b/.gitignore
@@ -289,3 +289,10 @@
 /utils/zenutils/source/zen_crypt/CMakeFiles
 /utils/zenutils/source/zen_crypt/cmake_install.cmake
 /utils/zenutils/source/zen_crypt/Makefile
+
+# /utils/regtools/
+/utils/regtools/headergen_v1
+/utils/regtools/headergen_v2
+/utils/regtools/regtool
+/utils/regtools/swiss_knife
+/utils/regtools/tester_v1