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/classes/autotools.bbclass

@@ -204,5 +204,8 @@ autotools_stage_all() {
 	rm -rf ${STAGE_TEMP}
 }
 
-EXPORT_FUNCTIONS do_configure do_install
+do_stage () {
+	autotools_stage_all
+}
 
+EXPORT_FUNCTIONS do_configure do_install

meta/classes/autotools_stage.bbclass

@@ -1,5 +1,2 @@
 inherit autotools
 
-do_stage () {
-	autotools_stage_all
-}