s390/dasd: Establish DMA alignment

s390/dasd: Establish DMA alignment

linux-next commit bf8d08532bc1 ("iomap: add support for dma aligned
direct-io") changes the alignment requirement to come from the block
device rather than the block size, and the default alignment
requirement is 512-byte boundaries. Since DASD I/O has page
alignments for IDAW/TIDAW requests, let's override this value to
restore the expected behavior.

Make this change for both ECKD and DIAG disciplines, as they both
would fall into this category. Leave FBA alone, since it is always
comprised of 512-byte blocks.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20220804213926.3361574-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>