When recovering partially written lines, the valid sector
count must be decreased by the number of padded sectors
in the line.

Update line recovery to take all ADDR_EMPTY(padded) sectors
into account.
Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>