Notify user when programming in quiet mode.

If you use the "prog" command in quiet mode, you don't see the messages
telling you what's being written. Instead, the only message you get is
"Erasing...", which leads to some confusion.

prog.c

@@ -38,6 +38,7 @@ int prog_flush(struct prog_data *prog)
 					  DEVICE_ERASE_MAIN, 0) < 0)
 			return -1;
 
+		printc("Programming...\n");
 		prog->have_erased = 1;
 	}