Rename pw_dumb_io to pw_sys_io

Rename pw_dumb_io facade and backends to use the more deliberate name
pw_sys_io moving forward.

Change-Id: I968480715967ab8de491856afa1b7692b973ed7e
diff --git a/pw_log_basic/CMakeLists.txt b/pw_log_basic/CMakeLists.txt
index c85276d..5c66fe0 100644
--- a/pw_log_basic/CMakeLists.txt
+++ b/pw_log_basic/CMakeLists.txt
@@ -16,8 +16,8 @@
   IMPLEMENTS_FACADE
     pw_log
   PRIVATE_DEPS
-    pw_dumb_io
     pw_string
+    pw_sys_io
 )
 
 target_include_directories(pw_log_basic PUBLIC public_overrides)