update: tftp: dfu: Extend update_tftp() function to support DFU

This code allows using DFU defined mediums for storing data received via
TFTP protocol.

It reuses and preserves functionality of legacy code at common/update.c.

The update_tftp() function now accepts parameters - namely medium device
name and its number (e.g. mmc 1).

Without this information passed old behavior is preserved.

Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/include/net.h b/include/net.h
index d09bec9..f1671e3 100644
--- a/include/net.h
+++ b/include/net.h
@@ -813,8 +813,18 @@
 /* get a random source port */
 unsigned int random_port(void);
 
-/* Update U-Boot over TFTP */
-int update_tftp(ulong addr);
+/**
+ * update_tftp - Update firmware over TFTP (via DFU)
+ *
+ * This function updates board's firmware via TFTP
+ *
+ * @param addr - memory address where data is stored
+ * @param interface - the DFU medium name - e.g. "mmc"
+ * @param devstring - the DFU medium number - e.g. "1"
+ *
+ * @return - 0 on success, other value on failure
+ */
+int update_tftp(ulong addr, char *interface, char *devstring);
 
 /**********************************************************************/