CVE-2023-53784

In the Linux kernel, the following vulnerability has been resolved:

drm: bridge: dw_hdmi: fix connector access for scdc

Commit 5d844091f237 ("drm/scdc-helper: Pimp SCDC debugs") changed the scdc
interface to pick up an i2c adapter from a connector instead. However, in
the case of dw-hdmi, the wrong connector was being used to pass i2c adapter
information, since dw-hdmi's embedded connector structure is only populated
when the bridge attachment callback explicitly asks for it.

drm-meson is handling connector creation, so this won't happen, leading to
a NULL pointer dereference.

Fix it by having scdc functions access dw-hdmi's current connector pointer
instead, which is assigned during the bridge enablement stage.

[narmstrong: moved Fixes tag before first S-o-b and added Reported-by tag]