Update KelvinCPU property

Match upstream change
https://github.com/renode/renode-infrastructure/commit/9220df6b

Change-Id: I156dd2111f304ab94d3d44d383ed2e874371dcad

shodan_infrastructure/KelvinCPU.cs

diff --git a/shodan_infrastructure/KelvinCPU.cs b/shodan_infrastructure/KelvinCPU.cs
index 59be135..385ec1f 100644
--- a/shodan_infrastructure/KelvinCPU.cs
+++ b/shodan_infrastructure/KelvinCPU.cs
@@ -149,6 +149,8 @@
         // No-op public API to match RiscVCPU
         public Int32 PerformanceInMips { get; set; }
 
+        public override string Architecture { get { return "kelvin"; } }
+
         public override ulong ExecutedInstructions => totalExecutedInstructions;
 
         public override ExecutionMode ExecutionMode