zonefs: select FS_IOMAP

Zonefs makes use of iomap internally, so it should also select iomap in
Kconfig.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>

fs/zonefs/Kconfig

@@ -2,6 +2,7 @@ config ZONEFS_FS
 	tristate "zonefs filesystem support"
 	depends on BLOCK
 	depends on BLK_DEV_ZONED
+	select FS_IOMAP
 	help
 	  zonefs is a simple file system which exposes zones of a zoned block
 	  device (e.g. host-managed or host-aware SMR disk drives) as files.