newt: Fix mfg crash with generated linker scripts

Author: m-gorecki

newt/pkg/bsp_package.go

@@ -135,7 +135,7 @@ func (bsp *BspPackage) resolveLinkerScriptSetting(
 				if len(vals) > 1 {
 					return nil, util.NewNewtError("Both autogenerated and custom linker scripts cannot be used. " +
 						"Newt handles either autogenerated linker script or a list of custom linker scripts.")
-				} else {
+				} else if bsp.yov != nil {
 					path, err := bsp.getAutogeneratedLinkerScriptPath()
 					if err != nil {
 						return nil, util.PreNewtError(err,