Depend on perl-doc:all instead of :native

This makes all dependency checks happy when cross compiling.

Change-Id: I426e755974f5375b1b2d80f1ded60f129e77288f
diff --git a/debian/control b/debian/control
index cffdf13..ee91fd9 100644
--- a/debian/control
+++ b/debian/control
@@ -19,7 +19,7 @@
                bison (>= 1:2.4),
                flex (>= 2.5.34),
                dpkg-dev (>= 1.15.1),
-               perl-doc:native,
+               perl-doc:all,
                libcap-dev [linux-any]
 Standards-Version: 3.9.3
 Homepage: http://gstreamer.freedesktop.org