examples: use CRG from litex.build.

examples/fast_scope_arty.py

@@ -6,10 +6,9 @@
 import sys
 
 from migen import *
-from migen.genlib.io import CRG
 
 from litex.build.generic_platform import *
-from litex.build.io import DifferentialInput
+from litex.build.io import DifferentialInput, CRG
 from litex.build.tools import write_to_file
 
 from litex.boards.platforms import arty

examples/targets/simple.py

@@ -2,7 +2,8 @@
 # License: BSD
 
 from migen import *
-from migen.genlib.io import CRG
+
+from litex.build.io import CRG
 
 from litex.soc.integration.soc_core import SoCMini