drm/bridge: cdns-mhdp8546: Fix use of uninitialized variable

'ret' could be uninitialized at the end of the function, although it's
not clear if that can happen in practice.

Fixes: 6a3608e ("drm: bridge: cdns-mhdp8546: Enable HDCP")
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231103-uninit-fixes-v2-3-c22b2444f5f5@ideasonboard.com

drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c

@@ -403,7 +403,8 @@ static int _cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp)
 
 static int _cdns_mhdp_hdcp_enable(struct cdns_mhdp_device *mhdp, u8 content_type)
 {
-	int ret, tries = 3;
+	int ret = -EINVAL;
+	int tries = 3;
 	u32 i;
 
 	for (i = 0; i < tries; i++) {