Fix ctypes -> uctypes for MicroPython v1.21.0

Author: yunkya2

ports/x68k/sample/dosgetdpb.py

@@ -1,6 +1,6 @@
 import x68k
 from struct import pack,unpack
-from ctypes import addressof
+from uctypes import addressof
 
 buf=bytearray(96)
 x68k.dos(x68k.d.GETDPB,pack('hl',0,addressof(buf)))

ports/x68k/sample/iocsline.py

@@ -1,6 +1,6 @@
 import x68k
 from struct import pack
-from ctypes import addressof
+from uctypes import addressof
 import random
 
 x68k.crtmod(14, True)