- Do not let individual KLD module unregister firmware image loaded by ispfw
or vice versa.
- Make 'kldunload ispfw' actually unregister all firmware images loaded by
ispfw, not just 'isp_1040'.
- Print which KLD module actually loaded the firmware image.
- Remove unused return value from do_load_fw() and do_unload_fw() and remove
duplicate sys/param.h while I am here.