target: Fail INQUIRY commands with EVPD==0 but PAGE CODE!=0

My draft of SPC-4 says:

    If the PAGE CODE field is not set to zero when the EVPD bit is set
    to zero, the command shall be terminated with CHECK CONDITION
    status, with the sense key set to ILLEGAL REQUEST, and the
    additional sense code set to INVALID FIELD IN CDB.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>