nvme: allocate aligned payloads for all nvme commands

nvme: allocate aligned payloads for all nvme commands

The kernel supports since v5.2 direct mapped DMA buffers to userspace.
Up to this point a bounce buffer was involved. Because the buffers are
now directly accessed by the device, the rules of alignment also apply
for the payloads.

Use the newly introduced nvme_alloc helper to allocate correctly aligned
payloads for all nvme commands.

Signed-off-by: Daniel Wagner <dwagner@suse.de>