ic: allow multi-arch clusters for GCP when feature gate enabled

Author: r4f4

pkg/types/installconfig.go

@@ -583,6 +583,8 @@ func MultiArchFeatureGateEnabled(platform string, fgs featuregates.FeatureGate)
 	switch platform {
 	case aws.Name:
 		return fgs.Enabled(features.FeatureGateMultiArchInstallAWS)
+	case gcp.Name:
+		return fgs.Enabled(features.FeatureGateMultiArchInstallGCP)
 	default:
 		return false
 	}

pkg/types/validation/installconfig_test.go

@@ -1423,6 +1423,17 @@ func TestValidateInstallConfig(t *testing.T) {
 				return c
 			}(),
 		},
+		{
+			name: "gcp cluster is heteregeneous",
+			installConfig: func() *types.InstallConfig {
+				c := validInstallConfig()
+				c.Platform = types.Platform{GCP: validGCPPlatform()}
+				c.Compute[0].Architecture = types.ArchitectureARM64
+				c.FeatureSet = "CustomNoUpgrade"
+				c.FeatureGates = []string{"MultiArchInstallGCP=true"}
+				return c
+			}(),
+		},
 		{
 			name: "valid cloud credentials mode",
 			installConfig: func() *types.InstallConfig {