block: fix the count of PGPGOUT for WRITE_SAME

block: fix the count of PGPGOUT for WRITE_SAME

BugLink: http://bugs.launchpad.net/bugs/1755179
commit 7c5a0dcf557c6511a61e092ba887de28882fe857 upstream.

The vm counters is counted in sectors, so we should do the conversation
in submit_bio.

Fixes: 74d46992e0d9 ("block: replace bi_bdev with a gendisk pointer and partitions index")
Cc: stable@vger.kernel.org
Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>