ioctl: pass data for Get/Set Features commands

ioctl: pass data for Get/Set Features commands

Several nvme_{g,s}et_features_*() functions take a data buffer
but don't provide it to the Get/Set Features commands.
Fix them to pass the data buffer to nvme_{g,s}et_features().

Getting the Host Memory Buffer feature also returns
a struct nvme_host_mem_buf_attrs data structure,
so make a nvme_get_features_host_mem_buf2() function
that takes in a data buffer to receive it.

Signed-off-by: Caleb Sander <csander@purestorage.com>