mpc: iim: Switch to common fsl_iim

Make all mpc512x code point to the new common fsl_iim driver, and remove the
former mpc512x-specific iim driver.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
diff --git a/include/configs/mpc5121ads.h b/include/configs/mpc5121ads.h
index 6e6af62..64ce52d 100644
--- a/include/configs/mpc5121ads.h
+++ b/include/configs/mpc5121ads.h
@@ -370,7 +370,7 @@
 /*
  * IIM - IC Identification Module
  */
-#undef CONFIG_IIM
+#undef CONFIG_FSL_IIM
 
 /*
  * EEPROM configuration