tools: kwboot: Wait blk_rsp_timeo when flushing

Use the blk_rsp_timeo variable when sleeping before flushing tty.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-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 82cfd9a..1477c0f 100644
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -1081,8 +1081,8 @@
 	 */
 	hdrsz += (KWBOOT_XM_BLKSZ - hdrsz % KWBOOT_XM_BLKSZ) % KWBOOT_XM_BLKSZ;
 
-	kwboot_printv("Waiting 2s and flushing tty\n");
-	sleep(2); /* flush isn't effective without it */
+	kwboot_printv("Waiting %d ms and flushing tty\n", blk_rsp_timeo);
+	usleep(blk_rsp_timeo * 1000);
 	tcflush(tty, TCIOFLUSH);
 
 	pnum = 1;