liblog: remove more unused code

Cleanup the headers; we really don't want to encourage any more
cutils/list.h usage...

Remove __android_log_uid() since the only remaining users are built
for device, so they can just use getuid() directly.

Test: build
Change-Id: I62be2c1e43d83807deaa9342afcc72459947cf15
diff --git a/liblog/logd_writer.cpp b/liblog/logd_writer.cpp
index 9a085ec..f49c59e 100644
--- a/liblog/logd_writer.cpp
+++ b/liblog/logd_writer.cpp
@@ -34,7 +34,6 @@
 
 #include <shared_mutex>
 
-#include <cutils/sockets.h>
 #include <private/android_filesystem_config.h>
 #include <private/android_logger.h>
 
@@ -113,7 +112,7 @@
   }
 
   /* logd, after initialization and priv drop */
-  if (__android_log_uid() == AID_LOGD) {
+  if (getuid() == AID_LOGD) {
     /*
      * ignore log messages we send to ourself (logd).
      * Such log messages are often generated by libraries we depend on