drm/bridge/analogix/anx6345: Cleanup on errors in anx6345_bridge_attach()

Another drive-by fix I found when fixing DP AUX adapter across the kernel
tree - make sure we don't leak resources (and by proxy-AUX adapters) on
failures in anx6345_bridge_attach() by unrolling on errors.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210219215326.2227596-13-lyude@redhat.com