nvme_dev_remove_admin could free dev->admin_q and the admin_tagset
while they are being accessed by nvme_dev_disable(), which can be called
by nvme_reset_work via nvme_remove_dead_ctrl.

Commit cb4bfda6 ("nvme-pci: fix hot removal during error handling")
intended to avoid requests being stuck on a removed controller by killing
the admin queue. But the later fix c8e9e9b7 ("nvme-pci: unquiesce
admin queue on shutdown"), together with nvme_dev_disable(dev, true)
right before nvme_dev_remove_admin() could help dispatch requests and
fail them early, so we don't need nvme_dev_remove_admin() any more.

Fixes: cb4bfda6

 ("nvme-pci: fix hot removal during error handling")
Signed-off-by: Casey Chen <cachen@purestorage.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>