ODROID-C5: showlogo: fix check cmd "hdmitx hpd" return value

Signed-off-by: YoungSoo Shin <shinys000114@gmail.com>
Change-Id: I5bbcd24f999a2a6c2bfd4ad19831575a3c12620f
diff --git a/cmd/showlogo.c b/cmd/showlogo.c
index 1fba0ba..025b1ad 100644
--- a/cmd/showlogo.c
+++ b/cmd/showlogo.c
@@ -34,7 +34,7 @@
 
 	/* hdmi config */
 	ret = run_command("hdmitx hpd", 0);
-	if (ret < 0) {
+	if (ret == 0) {
 		printf("hdmi not connected!\n");
 		return -1;
 	}