Kconfig: CONFIG_OF_PLATDATA doesn't really exist

There is no CONFIG_OF_PLATDATA, only CONFIG_SPL_OF_PLATDATA, so rename
the two references to CONFIG_OF_PLATDATA to CONFIG_SPL_OF_PLATDATA.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/common/spl/spl.c b/common/spl/spl.c
index a76ea3a..e512ee0 100644
--- a/common/spl/spl.c
+++ b/common/spl/spl.c
@@ -248,7 +248,7 @@
 		}
 	}
 	if (IS_ENABLED(CONFIG_SPL_DM)) {
-		/* With CONFIG_OF_PLATDATA, bring in all devices */
+		/* With CONFIG_SPL_OF_PLATDATA, bring in all devices */
 		ret = dm_init_and_scan(!CONFIG_IS_ENABLED(OF_PLATDATA));
 		if (ret) {
 			debug("dm_init_and_scan() returned error %d\n", ret);