autossh: add ssh client/server depends

It's not very useful without them.

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

package/autossh/Config.in

@@ -1,6 +1,7 @@
 config BR2_PACKAGE_AUTOSSH
 	bool "autossh"
 	depends on BR2_USE_MMU # fork()
+	depends on BR2_PACKAGE_DROPBEAR || BR2_PACKAGE_OPENSSH
 	help
 	  autossh is a program to start a copy of ssh and monitor it,
 	  restarting it as necessary should it die or stop passing traffic.