From: Lou Langholtz <ldl@aros.net>

This fourth patch simply removes the blksize_bits field from the nbd_device
struct and driver implementation.  How this field made it into this driver
to begin with is a mystery (where was Al Viro when that patch was
submitted??).  :-)

This patch modifies both drivers/block/nbd.c and include/linux/nbd.h files.
 It's intended to be applied incrementally on top of my third patch (for
enhanced diagnostics support).