spl: Convert spl_nand_load_image() to use linker list

Add a linker list declaration for this method and remove the explicit
switch() code.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/common/spl/spl.c b/common/spl/spl.c
index 9be256e..bbf8709 100644
--- a/common/spl/spl.c
+++ b/common/spl/spl.c
@@ -384,10 +384,6 @@
 		return loader->load_image(&bootdev);
 
 	switch (boot_device) {
-#ifdef CONFIG_SPL_NAND_SUPPORT
-	case BOOT_DEVICE_NAND:
-		return spl_nand_load_image(&bootdev);
-#endif
 #ifdef CONFIG_SPL_ONENAND_SUPPORT
 	case BOOT_DEVICE_ONENAND:
 		return spl_onenand_load_image(&bootdev);
diff --git a/common/spl/spl_nand.c b/common/spl/spl_nand.c
index 575de66..ed758e5 100644
--- a/common/spl/spl_nand.c
+++ b/common/spl/spl_nand.c
@@ -67,7 +67,7 @@
 	}
 }
 
-int spl_nand_load_image(void)
+static int spl_nand_load_image(struct spl_boot_device *bootdev)
 {
 	int err;
 	struct image_header *header;
@@ -145,3 +145,5 @@
 	return err;
 }
 #endif
+/* Use priorty 1 so that Ubi can override this */
+SPL_LOAD_IMAGE_METHOD(1, BOOT_DEVICE_NAND, spl_nand_load_image);
diff --git a/include/spl.h b/include/spl.h
index 47c1045..927f300 100644
--- a/include/spl.h
+++ b/include/spl.h
@@ -181,9 +181,6 @@
 		.load_image = __method, \
 	}
 
-/* NAND SPL functions */
-int spl_nand_load_image(struct spl_boot_device *bootdev);
-
 /* OneNAND SPL functions */
 int spl_onenand_load_image(struct spl_boot_device *bootdev);