spl: ymodem: Make SPL Y-Modem loader framework accessible

Expose SPL's Y-Modem core loader function via the common SPL header
file so it can be re-used for purposes other than loading U-Boot itself.

Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
diff --git a/common/spl/spl_ymodem.c b/common/spl/spl_ymodem.c
index 8ad580d..c02c056 100644
--- a/common/spl/spl_ymodem.c
+++ b/common/spl/spl_ymodem.c
@@ -68,8 +68,8 @@
 	return size;
 }
 
-static int spl_ymodem_load_image(struct spl_image_info *spl_image,
-				 struct spl_boot_device *bootdev)
+int spl_ymodem_load_image(struct spl_image_info *spl_image,
+			  struct spl_boot_device *bootdev)
 {
 	ulong size = 0;
 	int err;
diff --git a/include/spl.h b/include/spl.h
index 4359636..b5387ef 100644
--- a/include/spl.h
+++ b/include/spl.h
@@ -434,6 +434,9 @@
 		 int raw_part,
 		 unsigned long raw_sect);
 
+int spl_ymodem_load_image(struct spl_image_info *spl_image,
+			  struct spl_boot_device *bootdev);
+
 /**
  * spl_invoke_atf - boot using an ARM trusted firmware image
  */