spl, nand: add option to boot raw u-boot.bin image only

enable to boot only a raw u-boot.bin image from nand with the
CONFIG_SPL_NAND_RAW_ONLY define. This option saves space on
boards where spl space is low.

Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Andreas Bießmann <andreas.devel@googlemail.com>
Reviewed-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/include/spl.h b/include/spl.h
index 16b3566..b2e5bf7 100644
--- a/include/spl.h
+++ b/include/spl.h
@@ -35,6 +35,7 @@
 void preloader_console_init(void);
 u32 spl_boot_device(void);
 u32 spl_boot_mode(void);
+void spl_set_header_raw_uboot(void);
 void spl_parse_image_header(const struct image_header *header);
 void spl_board_prepare_for_linux(void);
 void __noreturn jump_to_image_linux(void *arg);