autotools: deprecate autotools_stage class

Move the functionality into autotools and ensure all our Poky recipes are no
longer using it.
Keep the autools_stage class around for OE compatability but just have it
inherit autools.

Signed-off-by: Joshua Lock <josh@linux.intel.com>

meta/packages/wbxml/wbxml2_0.9.2.bb

@@ -6,7 +6,7 @@ DEPENDS = "libxml2 sed-native expat"
 SRC_URI = "${SOURCEFORGE_MIRROR}/wbxmllib/${P}.tar.gz \
 	   file://no-doc-install.patch;patch=1"
 
-inherit autotools_stage pkgconfig
+inherit autotools pkgconfig
 
 do_configure_append() {
 	sed -i s:-I/usr/include::g Makefile