spl: Make the spl_nand_load_image static

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
diff --git a/common/spl/spl_nand.c b/common/spl/spl_nand.c
index 9a52500..2722fd3 100644
--- a/common/spl/spl_nand.c
+++ b/common/spl/spl_nand.c
@@ -12,7 +12,7 @@
 #include <fdt.h>
 
 #if defined(CONFIG_SPL_NAND_RAW_ONLY)
-int spl_nand_load_image(struct spl_image_info *spl_image,
+static int spl_nand_load_image(struct spl_image_info *spl_image,
 			struct spl_boot_device *bootdev)
 {
 	nand_init();