core156: Ship perl-Device-Modem

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/config/rootfiles/core/156/filelists/perl-Device-Modem b/config/rootfiles/core/156/filelists/perl-Device-Modem
new file mode 120000 (symlink)
index 0000000..ea70f08
--- /dev/null
+++ b/config/rootfiles/core/156/filelists/perl-Device-Modem
@@ -0,0 +1 @@
+../../../common/perl-Device-Modem
\ No newline at end of file