[SCSI] st.c: Improve sense output

Convert this:
st0: Error with sense data: <6>st: Current: sense key: Illegal Request
    Additional sense: Invalid field in cdb

To this:
st0: Current: sense key: Illegal Request
    Additional sense: Invalid field in cdb

Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Acked-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>