qcacmn: Add scheduler history

To help triage issues where the scheduler thread is processing slowly,
add a scheduler processing history for offline analysis. This can also
be useful in determining if a processing delay in some operation is
attributed to the scheduler thread or not.

Change-Id: Icfea17efc34b2a23d4f8b2baebe08db4e2f6ce8b
CRs-Fixed: 2307252

qdf/inc/qdf_time.h

@@ -306,6 +306,16 @@ static inline uint64_t qdf_get_log_timestamp(void)
 	return __qdf_get_log_timestamp();
 }
 
+/**
+ * qdf_get_log_timestamp_usecs() - get time stamp for logging in microseconds
+ *
+ * Return: The current logging timestamp normalized to microsecond precision
+ */
+static inline uint64_t qdf_get_log_timestamp_usecs(void)
+{
+	return qdf_log_timestamp_to_usecs(qdf_get_log_timestamp());
+}
+
 /**
  * qdf_get_monotonic_boottime - get monotonic kernel boot time
  * This API is similar to qdf_get_system_boottime but it includes