pw_data_link: Fix pw_multibuf build dep

The socket_data_link was depending on pw_multibuf:test_utils, when it
should have now been depending on pw_multibuf:chunk_region_tracker.

Change-Id: I92261f3ffdee67fe967e59ae0d4b57658fd0dce5
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/185657
Reviewed-by: Carlos Chinchilla <cachinchilla@google.com>
Commit-Queue: Aaron Green <aarongreen@google.com>

pw_data_link/BUILD.gn

diff --git a/pw_data_link/BUILD.gn b/pw_data_link/BUILD.gn
index ecda02f..7da71a6 100644
--- a/pw_data_link/BUILD.gn
+++ b/pw_data_link/BUILD.gn
@@ -49,7 +49,7 @@
   ]
   deps = [
     "$dir_pw_log",
-    "$dir_pw_multibuf:test_utils",
+    "$dir_pw_multibuf:chunk_region_tracker",
   ]
   sources = [ "socket_data_link.cc" ]
 }