Enable pyyaml nativesdk bake

Short term workaround pending upstream review:

https://patchwork.openembedded.org/patch/133725/

Change-Id: I63ed880adbc757c1385e0501edd27ef472b4a2be
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/common/recipes-devtools/python/python-pyyaml_%.bbappend b/common/recipes-devtools/python/python-pyyaml_%.bbappend
new file mode 100644
index 0000000..2a59083
--- /dev/null
+++ b/common/recipes-devtools/python/python-pyyaml_%.bbappend
@@ -0,0 +1 @@
+BBCLASSEXTEND += "nativesdk"