drm/mediatek: Initialize pointer before use to avoid undefiend behaviour

[Markus Elfring]

>> …
>>> ---
>>> Coverity Message:
>>> CID 1601557: (#1 of 1): Uninitialized pointer read (UNINIT)
>>> 3. uninit_use: Using uninitialized value next.
>>
>> May such information become a part for the final change description?
>>
> Ofcourse, it shouldn't be the part of the change description.

I suggest to reconsider this view once more.


> it is just for the reference to understand more about what the error message
> is generated by coverity scan.
Please take another look at possibilities how other contributors indicated
that some change opportunities were pointed out by advanced source code
analysis tools.

Regards,
Markus