update osm2pgsql (reduce memory usage)

diff --git a/osm2pgsql b/osm2pgsql
index 8d9087f1111f4a062158e8e6b10bfbceed90899b..5673b7fa0735b858cf573845c4787153b8ae106d 160000 (submodule)
--- a/osm2pgsql
+++ b/osm2pgsql
@@ -1 +1 @@
-Subproject commit 8d9087f1111f4a062158e8e6b10bfbceed90899b
+Subproject commit 5673b7fa0735b858cf573845c4787153b8ae106d