drm/bridge: anx7625: Convert to devm_i2c_new_dummy_device()

Simplify the resource management.

Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Xin Ji <xji@analogixsemi.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220706125254.2474095-2-hsinyi@chromium.org