brcm_fw_tool: sequence number was incorrect when wrapping past 999.

This in effect limited the system to max 999 upgrades.

brcm_fw_tool/image-jffs2.c

@@ -55,7 +55,7 @@ int gen_image_jffs2(const char *in_file, char *sequence_number)
 	}
 
 	sequence = atoi(sequence_number);
-	sprintf(fixed_sequence, "%03d", sequence+1);
+	sprintf(fixed_sequence, "%03d", (sequence+1) % 1000);
 
 	if (verbose)
 		fprintf(stderr, "New sequence: %s\n",fixed_sequence);