liblog: remove visibility macros

Visibility is managed through version scripts now.

Bug: 123349183
Test: build
Change-Id: Ia388611a2ec14d0ff9c3896cfe97ccdce17dbb8b
diff --git a/liblog/logd_reader.h b/liblog/logd_reader.h
index 0bba7cf..7c53cbb 100644
--- a/liblog/logd_reader.h
+++ b/liblog/logd_reader.h
@@ -22,6 +22,6 @@
 
 __BEGIN_DECLS
 
-LIBLOG_HIDDEN ssize_t __send_log_msg(char* buf, size_t buf_size);
+ssize_t __send_log_msg(char* buf, size_t buf_size);
 
 __END_DECLS