Take proper lock in ses_setphyspath_callback().

XPT_DEV_ADVINFO call should be protected by the lock of the specific
device it is addressed to, not the lock of SES device. In some weird
case, probably with hardware violating standards, it sometimes caused
NULL dereference due to race.

To protect from it further, add lock assertion to *_dev_advinfo().

MFC after: 1 week
Sponsored by: iXsystems, Inc.