Remove the monotonic option for logging

This has been around for ~5 years but there has been roughly no
adoption, so remove this as we clean up the logging code.

Future efforts may track the monotonic timestamp in all cases.

Test: logging unit tests
Change-Id: I55ed565669f923988e741f6b384141bba893630d
diff --git a/logcat/logcat.cpp b/logcat/logcat.cpp
index 8185f01..13023f2 100644
--- a/logcat/logcat.cpp
+++ b/logcat/logcat.cpp
@@ -459,7 +459,7 @@
                                             closedir);
     if (!dir.get()) return retval;
 
-    log_time now(android_log_clockid());
+    log_time now(CLOCK_REALTIME);
 
     size_t len = strlen(file);
     log_time modulo(0, NS_PER_SEC);