spl: nor: Don't allocate header on stack

spl_image_info.name contains a reference to legacy_img_hdr. If we allocate
the latter on the stack, it will be clobbered after we return. This was
addressed for NAND back in 06377c5a1fc ("spl: spl_legacy: Fix NAND boot on
OMAP3 BeagleBoard"), but that commit didn't fix NOR.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>
diff --git a/common/spl/spl_nor.c b/common/spl/spl_nor.c
index 79d4f1d..c141a9a 100644
--- a/common/spl/spl_nor.c
+++ b/common/spl/spl_nor.c
@@ -26,7 +26,7 @@
 static int spl_nor_load_image(struct spl_image_info *spl_image,
 			      struct spl_boot_device *bootdev)
 {
-	__maybe_unused const struct legacy_img_hdr *header;
+	struct legacy_img_hdr *header;
 	__maybe_unused struct spl_load_info load;
 
 	/*
@@ -41,7 +41,7 @@
 		 * Load Linux from its location in NOR flash to its defined
 		 * location in SDRAM
 		 */
-		header = (const struct legacy_img_hdr *)CONFIG_SYS_OS_BASE;
+		header = (void *)CONFIG_SYS_OS_BASE;
 #ifdef CONFIG_SPL_LOAD_FIT
 		if (image_get_magic(header) == FDT_MAGIC) {
 			int ret;
@@ -91,8 +91,8 @@
 	 * Load real U-Boot from its location in NOR flash to its
 	 * defined location in SDRAM
 	 */
-#ifdef CONFIG_SPL_LOAD_FIT
 	header = (const struct legacy_img_hdr *)spl_nor_get_uboot_base();
+#ifdef CONFIG_SPL_LOAD_FIT
 	if (image_get_magic(header) == FDT_MAGIC) {
 		debug("Found FIT format U-Boot\n");
 		load.bl_len = 1;
@@ -111,14 +111,11 @@
 
 	/* Legacy image handling */
 	if (IS_ENABLED(CONFIG_SPL_LEGACY_IMAGE_FORMAT)) {
-		struct legacy_img_hdr hdr;
-
 		load.bl_len = 1;
 		load.read = spl_nor_load_read;
-		spl_nor_load_read(&load, spl_nor_get_uboot_base(), sizeof(hdr), &hdr);
 		return spl_load_legacy_img(spl_image, bootdev, &load,
 					   spl_nor_get_uboot_base(),
-					   &hdr);
+					   header);
 	}
 
 	return -EINVAL;