Clean documetation

The qemu Makefiles don't remove the generated documentation files.

The attached patch adds removal of these files to the 'distclean' rule.

Paul

Index: Makefile
===================================================================
RCS file: /cvsroot/qemu/qemu/Makefile,v
retrieving revision 1.90

diff -u -p -r1.90 Makefile
@@ -44,7 +44,7 @@ ifdef CONFIG_KQEMU
 endif
 
 distclean: clean
-	rm -f config-host.mak config-host.h
+	rm -f config-host.mak config-host.h $(DOCS)
 	for d in $(TARGET_DIRS); do \
 	rm -rf $$d || exit 1 ; \
         done