LU-13181 o2ib: fix page mapping error

LU-13181 o2ib: fix page mapping error

IB DMA mapping can merge a physically continues page region into
single one.
It's confused a kiblnd_fmr_pool_map function who expect to see all
fragments mapped.
It's generate a error
 (o2iblnd.c:1926:kiblnd_fmr_pool_map()) Failed to map mr 1/16 elements

By study an IB code, it looks ib_map_mr_sg return code should checked
against of result of ib_dma_map_sg instead of original fragments
count, same data should be used as argument of ib_map_mr_sg function.

Lustre-commit: 40385cda7afbd62faf7de2e956f0c7f4fa1a3fed
Lustre-change: https://review.whamcloud.com/37388

Test-Parameters: trivial
Cray-bug-id: LUS-8139
Signed-off-by: Alexey Lyashkov <c17817@cray.com>
Change-Id: I3b845ae54d8659d4045921f519effcf0a4428e49
Reviewed-on: https://review.whamcloud.com/41303
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>