Add unreclaimable category in rss_stat

This was introduced in 4.19, used by kgsl drivers

Bug: 156290326
Change-Id: I49508085c3d7caf445de9d09402a51a252a5d7ee
diff --git a/src/trace_processor/importers/ftrace/rss_stat_tracker.cc b/src/trace_processor/importers/ftrace/rss_stat_tracker.cc
index f6f3548..8c5e8f6 100644
--- a/src/trace_processor/importers/ftrace/rss_stat_tracker.cc
+++ b/src/trace_processor/importers/ftrace/rss_stat_tracker.cc
@@ -32,7 +32,9 @@
   rss_members_.emplace_back(context->storage->InternString("mem.swap"));
   rss_members_.emplace_back(context->storage->InternString("mem.rss.shmem"));
   rss_members_.emplace_back(
-      context->storage->InternString("mem.rss.unknown"));  // Keep this last.
+      context->storage->InternString("mem.unreclaimable"));
+  rss_members_.emplace_back(
+      context->storage->InternString("mem.unknown"));  // Keep this last.
 }
 
 void RssStatTracker::ParseRssStat(int64_t ts, uint32_t pid, ConstBytes blob) {