btrfs: use raid_attr table in calc_stripe_length for nparity

The table is already used for ncopies, replace open coding of stripes
with the raid_attr value.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2019-05-14 01:59:54 +02:00
commit e4f6c6be81