common: Move do_tftpb() to net.h

This function belongs in the network header file. Move it.

Signed-off-by: Simon Glass <sjg@chromium.org>

include/net.h

@@ -50,6 +50,17 @@ struct in_addr {
 	__be32 s_addr;
 };
 
+/**
+ * do_tftpb - Run the tftpboot command
+ *
+ * @cmdtp: Command information for tftpboot
+ * @flag: Command flags (CMD_FLAG_...)
+ * @argc: Number of arguments
+ * @argv: List of arguments
+ * @return result (see enum command_ret_t)
+ */
+int do_tftpb(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[]);
+
 /**
  * An incoming packet handler.
  * @param pkt    pointer to the application packet