resources: Added pthreads bin dirs to .gitignore

Change-Id: I722456ea9f0fca28dc323cb30bab901cc0b980fd
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-resources/+/29302
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: Jason Lowe-Power <power.jg@gmail.com>
diff --git a/src/pthreads/.gitignore b/src/pthreads/.gitignore
new file mode 100644
index 0000000..fc8c9b0
--- /dev/null
+++ b/src/pthreads/.gitignore
@@ -0,0 +1 @@
+/bin.*