spl: Move spl_board_load_image() into a generic header

At present this is only used on ARM and sandbox, but it is just as
applicable to other architectures. Move the function prototype into the
generic SPL header.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/include/asm/spl.h

@@ -33,15 +33,6 @@ enum {
 };
 #endif
 
-/**
- * Board specific load method for boards that have a special way of loading
- * U-Boot, which does not fit with the existing SPL code.
- *
- * @return 0 on success, negative errno value on failure.
- */
-
-int spl_board_load_image(void);
-
 /* Linker symbols. */
 extern char __bss_start[], __bss_end[];
 

arch/sandbox/include/asm/spl.h

@@ -8,14 +8,6 @@
 
 #define CONFIG_SPL_BOARD_LOAD_IMAGE
 
-/**
- * Board-specific load method for boards that have a special way of loading
- * U-Boot, which does not fit with the existing SPL code.
- *
- * @return 0 on success, negative errno value on failure.
- */
-int spl_board_load_image(void);
-
 enum {
 	BOOT_DEVICE_BOARD,
 };

include/spl.h

@@ -152,4 +152,13 @@ bool spl_was_boot_source(void);
  * @return 0 on success, otherwise error code
  */
 int spl_dfu_cmd(int usbctrl, char *dfu_alt_info, char *interface, char *devstr);
+
+/**
+ * Board-specific load method for boards that have a special way of loading
+ * U-Boot, which does not fit with the existing SPL code.
+ *
+ * @return 0 on success, negative errno value on failure.
+ */
+int spl_board_load_image(void);
+
 #endif