sgi/acs: Allow this script to be usable on RD-N2 platform

RD-N2 platform can be validated using ACS test suite. So enable
usability of this script on RD-N2 platform.

Change-Id: If6ae08fe574640602614fae469a325111d222eee
Signed-off-by: Pranav Madhu <pranav.madhu@arm.com>

sgi/acs.sh

@@ -39,6 +39,7 @@ declare -A platforms_rdinfra
 platforms_rdinfra[rdn1edge]=1
 platforms_rdinfra[rde1edge]=1
 platforms_rdinfra[rdv1]=1
+platforms_rdinfra[rdn2]=1
 
 __print_examples()
 {