SDMA RLC queues do not currently remove their doorbell mapping. This can
cause issues re-registering the queue and prevents the pending doorbells
feature from working. In addition the data value of the doorbell (the
ring buffer rptr) is not saved, leading to UB when this workaround is
used.
This commit removes the doorbell mapping from the gpu device when the
SDMA engine unmaps an RLC queue and copies the next doorbell value to
the pending packet as was originally intended.
Change-Id: Ifd551450f439c065579afcf916f8ff192e7598ab
07f6b7c59c