s390x/css: sense data endianness

s390x/css: sense data endianness

We keep the device's sense data in a byte array (following the
architecture), but the ecws are an array of 32 bit values. If we
just blindly copy the values, the sense data will change from
de-facto BE data to de-facto cpu-endian data, which means we end
up doing an incorrect conversion on LE hosts.

Let's just explicitly convert to cpu-endianness while assembling
the irb.

Reported-by: Andy Lutomirski <[email protected]>
Tested-by: Andy Lutomirski <[email protected]>
Signed-off-by: Cornelia Huck <[email protected]>
Reviewed-by: Christian Borntraeger <[email protected]>