Fix stream table entry (STE) initialization and removal.
For PCI devices we have entire L1 descriptor for every session ID (SID),
but for non-PCI (e.g. Display Processing Unit DPU), a single L1
descriptor serves multiple SIDs.
So prevent re-initialization of L1 descriptor if already initialized.
Don't free entire L1 descriptor on every STE removal.

Sponsored by: UKRI