gein.sh: Advise to submit an issue if arch not found

gein.sh

@@ -143,12 +143,13 @@ KernelConfig="$Source/usr/src/linux/4.16.config"
 #
 
 case "$(uname -m)" in
-    x86_64)    CPUArch="amd64";;
     i386|i486) CPUArch="i486";;
     i686|x86)  CPUArch="i686";;
+    x86_64)    CPUArch="amd64";;
 
     *)
         echo "gein: CPU arch has not been defined yet"
+	echo "gein: Submit an issue with the output of 'uname -m'"
         exit
 esac