libnewt-python: Add nativesdk

Add nativesdk for libnewt-python.

(From OE-Core rev: b992be195821e110691434e4a743b753bc04b3c4)

Signed-off-by: Zheng Ruoqin <zhengrq.fnst@cn.fujitsu.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/newt/libnewt-python_0.52.20.bb

@@ -25,4 +25,4 @@ PACKAGES_remove = "whiptail"
 
 FILES_${PN} = "${PYTHON_SITEPACKAGES_DIR}/*"
 
-BBCLASSEXTEND = "native"
+BBCLASSEXTEND = "native nativesdk"