IB/iser: Don't suppress send completions

In order to complete a scsi command and guarantee that the HCA will never
perform an access violation when retrying a send operation we must
complete a scsi request only when both send and receive completions has
arrived. This is a preparation commit that remove the send completions
suppression. Next step will be taking care of the local invalidation
mechanism and adding a reference counter for commands.  Currently, we
don't do anything upon getting the send completion and just "consume" it.

Link: https://lore.kernel.org/r/20211215135721.3662-5-mgurtovoy@nvidia.com


Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Israel Rukshin <israelr@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>