tools: kwboot: Change retry loop from decreasing to increasing

This patch does not change behavior of the code, just allows to implement
new changes more easily.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/tools/kwboot.c b/tools/kwboot.c
index 5d7cb7a..16c5a84 100644
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -925,7 +925,7 @@
 
 	*done_print = 0;
 
-	retries = 16;
+	retries = 0;
 	do {
 		rc = kwboot_tty_send(fd, block, sizeof(*block));
 		if (rc)
@@ -944,7 +944,7 @@
 
 		if (!allow_non_xm && c != ACK)
 			kwboot_progress(-1, '+');
-	} while (c == NAK && retries-- > 0);
+	} while (c == NAK && retries++ < 16);
 
 	if (non_xm_print)
 		kwboot_printv("\n");
@@ -973,7 +973,7 @@
 
 	kwboot_printv("Finishing transfer\n");
 
-	retries = 16;
+	retries = 0;
 	do {
 		rc = kwboot_tty_send_char(fd, EOT);
 		if (rc)
@@ -982,7 +982,7 @@
 		rc = kwboot_xm_recv_reply(fd, &c, 0, NULL, 0, NULL);
 		if (rc)
 			return rc;
-	} while (c == NAK && retries-- > 0);
+	} while (c == NAK && retries++ < 16);
 
 	return _xm_reply_to_error(c);
 }