drm/vc4: drv: Add error handding for bind

There is a problem that if vc4_drm bind fails, a memory leak occurs on
the drm_property_create side. Add error handding for drm_mode_config.

Signed-off-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20201027041442.30352-2-hoegeun.kwon@samsung.com