CVE-2026-98998: drm/bridge: th1520-dw-hdmi: Fix remove() callback

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

drm/bridge: th1520-dw-hdmi: Fix remove() callback

This driver stores struct th1520hdmi in platform drvdata, but th1520dwhdmiremove() was reading it back as struct dwhdmi and passing it to dwhdmiremove(), so teardown runs on the wrong pointer.

Retrieve struct th1520hdmi from platform drvdata and pass hdmi->dwhdmi to dwhdmiremove().