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/logd/tests/logd_test.cpp b/logd/tests/logd_test.cpp
index 1dd5c86..55737e9 100644
--- a/logd/tests/logd_test.cpp
+++ b/logd/tests/logd_test.cpp
@@ -606,7 +606,7 @@
     // A few tries to get it right just in case wrap kicks in due to
     // content providers being active during the test.
     int i = 5;
-    log_time start(android_log_clockid());
+    log_time start(CLOCK_REALTIME);
     start.tv_sec -= 30;  // reach back a moderate period of time
 
     while (--i) {
@@ -682,7 +682,7 @@
             if (msg > start) {
                 start = msg;
                 start.tv_sec += 30;
-                log_time now = log_time(android_log_clockid());
+                log_time now = log_time(CLOCK_REALTIME);
                 if (start > now) {
                     start = now;
                     --start.tv_sec;