qla2xxx: prevent speculative execution

qla2xxx: prevent speculative execution

Since the handle value in functions qlafx00_status_entry()
and qlafx00_multistatus_entry() seems to be controllable
by userspace and later on conditionally (upon bound check)
used to resolve req->outstanding_cmds, insert an observable
speculation barrier before its usage. This should prevent
observable speculation on that branch and avoid kernel
memory leak.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Orabug: 27340445
CVE: CVE-2017-5753

Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com>
Reviewed-by: John Haxby <john.haxby@oracle.com>
Signed-off-by: Kirtikar Kashyap <kirtikar.kashyap@oracle.com>