Fix maintainer-clean make target

Add the missing MAINTAINERCLEANFILES to makefile.am.

---
Hi Catalin,

Here's a minor fix for the arm64 bootwrapper to make 'make maintainer-clean' work. You can try it with something this:

autoreconf -i
./configure ...
make maintainer-clean
git ls-files -o

-Geoff

 Makefile.am | 3 +++
 1 file changed, 3 insertions(+)

index 5791ad1..c911e51 100644
@@ -88,3 +88,6 @@ fdt.dtb: $(KERNEL_DTB) Makefile gen-cpu-nodes.sh
 
 # The filesystem archive might not exist if INITRD is not being used
 .PHONY: all clean $(FILESYSTEM)
+
+MAINTAINERCLEANFILES = aclocal.m4 compile config.* configure install-sh \
+	Makefile.in missing

1.9.1

Thanks. Applied.

Catalin