[SCSI] mpt2sas: Fix for dead lock occurring between host_lock and sas_device_lock

[SCSI] mpt2sas: Fix for dead lock occurring between host_lock and sas_device_lock

Fix for dead lock occurring between host_lock and sas_device_lock.

The deadlock is between two spin locks, between the shost->host_lock
and driver ioc->sas_device_lock.

The fix is to rearrange the code in the  FW/Driver device removal
handshake so the ioc->sas_device_lock is not occurring when the
shost->host_lock is taken.

[jejb: zero initialise sas_address to fix spurious compiler warning]
Signed-off-by: Nagalakshmi Nandigama <nagalakshmi.nandigama@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>