Check status of cam_periph_hold() inside cdclose().  If cd device was invalidated while open, cam_periph_hold() will return error and won't get the reference.  Following reference release will crash the system.
Check status of cam_periph_hold() inside cdclose().  If cd device was
invalidated while open, cam_periph_hold() will return error and won't
get the reference.  Following reference release will crash the system.

Sponsored by:	iXsystems, Inc.
MFC after:	3 days

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