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/mecp5123.h b/include/configs/mecp5123.h
index af30257..c4f245b 100644
--- a/include/configs/mecp5123.h
+++ b/include/configs/mecp5123.h
@@ -275,7 +275,7 @@
 /*
  * IIM - IC Identification Module
  */
-#undef CONFIG_IIM
+#undef CONFIG_FSL_IIM
 
 /*
  * EEPROM configuration