amdgpu: Add CH7218 PCON to the VRR whitelist

[henrikx]

Adds CH7218 to VRR whitelist

Chrontel CH7218 found in Ugreen DP -> HDMI 2.1 adapter (model 85564)
works perfectly with VRR after testing. VRR and FreeSync compatibility
is explicitly advertised as a feature so it's addition is a formality.

This is the same as this: https://github.com/bazzite-org/kernel-bazzite/blob/bazzite-6.17/patch-4-amdgpu-vrr-whitelist.patch

Originally Signed-off-by: Tomasz Pakuła tomasz.pakula.oficjalny@gmail.com

Fixes
ublue-os/bazzite#4532 and
#73

[pastaq]

Thanks for this.

Please update the patch header to include the origin source as per the guidance

Additionally, please as source tagging & signatures as needed. When pulling from LKML:
b4 am -cl <url>

When cherry-picking from OOT:
git cherry-pick -sex <sha>

This helps us track the source of each patch and helps better manage them during version updates. Thanks.