lightnvm: use end_io callback instead of instance

When the lightnvm core had the "gennvm" layer between the device and the
target, there was a need for the core to be able to figure out which
target it should send an end_io callback to. Leading to a "double"
end_io, first for the media manager instance, and then for the target
instance. Now that core and gennvm is merged, there is no longer a need
for this, and a single end_io callback will do.

Signed-off-by: Matias Bjørling <matias@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/lightnvm/rrpc.h

@@ -102,9 +102,6 @@ struct rrpc_lun {
 };
 
 struct rrpc {
-	/* instance must be kept in top to resolve rrpc in unprep */
-	struct nvm_tgt_instance instance;
-
 	struct nvm_tgt_dev *dev;
 	struct gendisk *disk;