NVMe: Merge issue on character device bring-up

A recent patch made it possible to bring up the character handle when the
device is responsive but not accepting a set-features command. Another
recent patch moved the initialization that requires we move where the
checks for this condition occur. This patch merges these two ideas so
it works much as before.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>