SCP: Add test config for dual-chip RD-N1-Edge

Add RD-N1-Edge-Dual to SCP's test config. SCP code for RD-N1-Edge and
RD-N1-Edge-Dual is same, hence the dual-chip reuses
scp_config/fvp-rdn1edge file. Also, the test uses existing TF-A
config for the Busybox linux boot test on RD-N1-Edge-Dual FVP.

Change-Id: Ifb1766d48e166152bbe56839fe344d2541cec11f
diff --git a/group/scp-boot-tests/fvp-rdn1edge,fvp-rdn1edgex2-tbb:fvp-linux.sgi-fip.sgi-rdn1edgex2-debug b/group/scp-boot-tests/fvp-rdn1edge,fvp-rdn1edgex2-tbb:fvp-linux.sgi-fip.sgi-rdn1edgex2-debug
new file mode 100644
index 0000000..c75b524
--- /dev/null
+++ b/group/scp-boot-tests/fvp-rdn1edge,fvp-rdn1edgex2-tbb:fvp-linux.sgi-fip.sgi-rdn1edgex2-debug
@@ -0,0 +1,6 @@
+#
+# Copyright (c) 2019, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+