syslinux: add hash

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

boot/syslinux/syslinux.hash

@@ -0,0 +1,2 @@
+# From https://www.kernel.org/pub/linux/utils/boot/syslinux/sha256sums.asc
+sha256	afa31b7cbf72e1c0c1752a0636ba724ce01c0e374366e46e61db6862b4685478	syslinux-6.02.tar.xz