drm/omap: fix uninitialized ret variable

drm/omap: fix uninitialized ret variable

[ Upstream commit 77eeac24b10fc84d3ffd5b11a897dff88dde244d ]

audio_config function for both HDMI4 and HDMI5 return uninitialized
value as the error code if the display is not currently enabled. For
some reason this has not caused any issues.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180329104038.29154-1-tomi.valkeinen@ti.com
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>