file-posix: Check bs->bl.zoned for zone info

file-posix: Check bs->bl.zoned for zone info

Instead of checking bs->wps or bs->bl.zone_size for whether zone
information is present, check bs->bl.zoned.  That is the flag that
raw_refresh_zoned_limits() reliably sets to indicate zone support.  If
it is set to something other than BLK_Z_NONE, other values and objects
like bs->wps and bs->bl.zone_size must be non-null/zero and valid; if it
is not, we cannot rely on their validity.

Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230824155345.109765-3-hreitz@redhat.com>
Reviewed-by: Sam Li <faithilikerun@gmail.com>