Build: Enable rss/rdfremont build

Add configuration for RSS RD-Fremont.

Signed-off-by: Joel Goddard <joel.goddard@arm.com>
Change-Id: I1900db48a41e361615bb22689cc7b4f92c0bb88b
diff --git a/build_helper/build_helper_config_maps.py b/build_helper/build_helper_config_maps.py
index c9022e2..a4e248f 100644
--- a/build_helper/build_helper_config_maps.py
+++ b/build_helper/build_helper_config_maps.py
@@ -25,6 +25,7 @@
     "arm/corstone1000"                   : "corstone1000",
     "arm/mps3/corstone310/fvp"           : "corstone310",
     "arm/rss/tc"                         : "RSS",
+    "arm/rss/rdfremont"                  : "RSS_RDFremont",
     "cypress/psoc64"                     : "psoc64",
     "lairdconnectivity/bl5340_dvk_cpuapp": "BL5340",
     "nordic_nrf/nrf5340dk_nrf5340_cpuapp": "nrf5340dk",