ctl: Use CAM_PRIORITY_NORMAL for queued CCBs

Previously this was using CAM_PRIORITY_NONE which tripped over the
assertion added in b4b166b8c46b8.

PR: 293076
Reported by: Ken J. Thomson <thomsonk@yandex.com>
Reviewed by: imp
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D56995