In the same way that fallback in receive_frame() needs to be repeated
until we get a working decoder, we have to do the same thing in
reinit(). Calling force_fallback() only once can still yield a non
functional decoder.
The reason why we have these multiple paths which each require their
own fallback logic is that we can fail at different stages:
* hwdec init
* decoder init <- repeated fallback was missing here
* frame decoding
Fixes#12084
Philip Langdale
e8144ac231