package/libss7: propagate dependency from dahdi-tools

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 76e6837cd670449740f21015a406d722e089a084)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libss7/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_LIBSS7
 	bool "libss7"
+	depends on BR2_USE_MMU # dahdi-tools <- perl
 	depends on BR2_LINUX_KERNEL
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_PACKAGE_DAHDI_LINUX