pw_system/cmake: Correct dependency for pw_system.init

Change-Id: I3ad4d60faaff1a061d7a3850734d5d501a88ac2c
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/110120
Pigweed-Auto-Submit: Ewout van Bekkum <ewout@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/pw_system/CMakeLists.txt b/pw_system/CMakeLists.txt
index 457cc81..52e9f22 100644
--- a/pw_system/CMakeLists.txt
+++ b/pw_system/CMakeLists.txt
@@ -96,7 +96,7 @@
   PRIVATE_DEPS
         pw_system.log
         pw_system.rpc_server
-        pw_rpc.nanopb.echo_service
+        pw_rpc.pwpb.echo_service
         pw_thread.thread
   SOURCES
     init.cc