[PATCH v4] nvmet: clean up DH group state on initialization failure

[Sreeraj S Kurup]

Thanks, Hannes.

I kept the cleanup in a common "err:" path to avoid duplicating the teardown 
logic across multiple failure paths.

The diff looks larger mainly because I removed the existing "else" block after 
introducing "goto err" for error handling. This allows the successful initialization 
path to remain linear, with all failures handled through the common cleanup section.

Thanks for the review!

Sreeraj