CAM: Keep periph_links when restoring CCB in camperiphdone().

While recovery command executed, some other commands from the periph
may complete, that may affect periph_links of this CCB. So restoring
original CCB we must keep current periph_links as more up to date.

I've found this triggering assertions with debug kernel and suspect
some memory corruptions otherwise when spun down disk receives two
or sometimes more concurrent requests.

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