nvme-pci: Fix abort command id

The request tag is no longer the only component of the command id.

Fixes: e7006de6

 ("nvme: code command_id with a genctr for use-after-free validation")
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>