Enable lowmemory trace events in atrace

Enable collection of lowmemory events in atrace as a category. These
events have been available in the kernel, but not exposed via atrace.

Bug: https://github.com/catapult-project/catapult/issues/3557
Test: Run "atrace memreclaim", trigger LMK events.
Change-Id: I92140518796bdda8b302d566d7d78e2129b9839c
diff --git a/cmds/atrace/atrace.cpp b/cmds/atrace/atrace.cpp
index 8d9442b..c79692e 100644
--- a/cmds/atrace/atrace.cpp
+++ b/cmds/atrace/atrace.cpp
@@ -172,6 +172,7 @@
         { REQ,      "events/vmscan/mm_vmscan_direct_reclaim_end/enable" },
         { REQ,      "events/vmscan/mm_vmscan_kswapd_wake/enable" },
         { REQ,      "events/vmscan/mm_vmscan_kswapd_sleep/enable" },
+        { REQ,      "events/lowmemorykiller/enable" },
     } },
     { "regulators",  "Voltage and Current Regulators", 0, {
         { REQ,      "events/regulator/enable" },