dax: drop size parameter to ->direct_access()

None of the implementations currently use it.  The common
bdev_direct_access() entry point handles all the size checks before
calling ->direct_access().

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --cc arch/powerpc/sysdev/axonram.c
Simple merge

diff --cc drivers/block/brd.c
Simple merge

diff --cc drivers/nvdimm/pmem.c
Simple merge

diff --cc drivers/s390/block/dcssblk.c
Simple merge

diff --cc fs/block_dev.c
Simple merge

diff --cc include/linux/blkdev.h
Simple merge