Finish conversion CONFIG_SYS_NAND_SELF_INIT to Kconfig

In order to finish this conversion we need to add a symbols for
SPL_SYS_NAND_SELF_INIT and TPL_SYS_NAND_SELF_INIT as there are cases
there where we need to, or need to not, use that framework as things
stand.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/mtd/nand/raw/nand.c b/drivers/mtd/nand/raw/nand.c
index 59ad139..4b5560d 100644
--- a/drivers/mtd/nand/raw/nand.c
+++ b/drivers/mtd/nand/raw/nand.c
@@ -76,7 +76,7 @@
 	return 0;
 }
 
-#ifndef CONFIG_SYS_NAND_SELF_INIT
+#if !CONFIG_IS_ENABLED(SYS_NAND_SELF_INIT)
 static void nand_init_chip(int i)
 {
 	struct nand_chip *nand = &nand_chip[i];
@@ -155,7 +155,7 @@
 		return;
 	initialized = 1;
 
-#ifdef CONFIG_SYS_NAND_SELF_INIT
+#if CONFIG_IS_ENABLED(SYS_NAND_SELF_INIT)
 	board_nand_init();
 #else
 	int i;