config: add rainier 1s4u support

IBM is introducing a new variant of its rainier 4u machine that requires
a different entity manager config. From a host data perspective though,
everything is the same so just point to the same data.

Tested:
- Booted up system with 1s4u IM keyword and new entity manager config
  and verified correct links for host data were still in place.
  i.e. DEVTREE -> DEVTREE.RAINIER_4U_XML

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: If20df4aeb6d9fcc59df945f6e8ca0f166cdb67f6
diff --git a/item_updater_main.cpp b/item_updater_main.cpp
index 7249f52..c563cbe 100644
--- a/item_updater_main.cpp
+++ b/item_updater_main.cpp
@@ -74,6 +74,7 @@
                     {"ibm,everest"s, {".EVEREST_XML"s, ".P10"s}},
                     {"ibm,rainier-2u"s, {".RAINIER_2U_XML"s, ".P10"s}},
                     {"ibm,rainier-4u"s, {".RAINIER_4U_XML"s, ".P10"s}},
+                    {"ibm,rainier-1s4u"s, {".RAINIER_4U_XML"s, ".P10"s}},
                 }};
                 auto hostFirmwareDirectory = "/media/hostfw/running"s;
                 auto logCallback = [](const auto& path, auto& ec) {