f2fs: Reset sequential zones on zoned block devices

commit f46e8809e88d113ba096bcfc772b5182ce00b941 upstream.

When a zoned block device is mounted, discarding sections
contained in sequential zones must reset the zone write pointer.
For sections contained in conventional zones, the regular discard
is used if the drive supports it.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>