logd: liblog: logcat: switch to android_log_clockid() (2)

android_log_timestamp returns the property leading letter,
it is better to return a clockid_t with android_log_clockid()

Bug: 23668800
Change-Id: I38dee773bf3844177826b03a26b03215c79a5359
diff --git a/logcat/logcat.cpp b/logcat/logcat.cpp
index 22645f5..0c59f23 100644
--- a/logcat/logcat.cpp
+++ b/logcat/logcat.cpp
@@ -398,11 +398,9 @@
         return retval;
     }
 
-    log_time now(CLOCK_REALTIME);
-    bool monotonic = android_log_timestamp() == 'm';
-    if (monotonic) {
-        now = log_time(CLOCK_MONOTONIC);
-    }
+    clockid_t clock_type = android_log_clockid();
+    log_time now(clock_type);
+    bool monotonic = clock_type == CLOCK_MONOTONIC;
 
     std::string directory;
     char *file = strrchr(outputFileName, '/');