The dax is only supported on pfn type pmem devices since commit
f467fee4 ("block: move the dax flag to queue_limits"). Trying
to mount DAX filesystem fails with this error:
 mount: : wrong fs type, bad option, bad superblock on /dev/pmem7,
          missing codepage or helper program, or other error.
 dmesg(1) may have more information after failed mount system call.
 dmesg: EXT4-fs (pmem7): DAX unsupported by block device.

Fix the problem by adding dax flag setting for the missed case.

Fixes: f467fee4 ("block: move the dax flag to queue_limits")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/20240809031155.2837271-1-chengzhihao1@huawei.comSigned-off-by: Ira Weiny <ira.weiny@intel.com>