nvme: simplify stripe quirk

Some OEMs believe they own the Identify Controller vendor specific
region and will repurpose it with their own values. While not common,
we can't rely on the PCI VID:DID to tell use how to decode the field
we reserved for this as the stripe size so we need to do something else
for the list of devices using this quirk.

The field was supposed to allow flexibility on the device's back-end
striping, but it turned out that never materialized; the chunk is always
the same as MDTS in the products subscribing to this quirk, so this
patch removes the stripe_size field and sets the chunk to the max hw
transfer size for the devices using this quirk.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>