btrfs: scrub: run relocation repair when/only needed

When btrfs scrub finds an error, it reads mirrors to find correct data. If
all the errors are fixed, sctx->error_bitmap is cleared for the stripe
range. However, in the zoned mode, it runs relocation to repair scrub
errors when the bitmap is *not* empty, which is a flipped condition.

Also, it runs the relocation even if the scrub is read-only. This was
missed by a fix in commit 1f2030ff ("btrfs: scrub: respect the
read-only flag during repair").

The repair is only necessary when there is a repaired sector and should be
done on read-write scrub. So, tweak the condition for both regular and
zoned case.

Fixes: 54765392 ("btrfs: scrub: introduce helper to queue a stripe for scrub")
Fixes: 1f2030ff ("btrfs: scrub: respect the read-only flag during repair")
CC: stable@vger.kernel.org # 6.6+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>