kernel/isp: Unify firmware handling with the rest of the system.

kernel/isp: Unify firmware handling with the rest of the system.

* Convert firmware binary data from C arrays in a header files to
  uuencode .uu files. Byte order of the firmware image is
  little-endian. As far as DragonFly BSD supports only little-endian
  architectures it's ok. But in case of a big-endian architecture the
  byte order must be changed before firmware is processed by the isp
  driver.

* Move the .uu images to a sys/contrib/dev/isp.

* Add a script for conversion of firmware stored in arrays in the C
  header files to .uu files. This is for getting the firmware changes
  from the other BSD systems more easily.

* Remove use of ispfw module that contains firmwares for all of the
  isp.4 driver devices. User can pick a module for a particular device
  instead of having firmwares for all of the devices loaded.

* Document that the kitchen sink ispfw.ko module with all firmware is
  gone.

Submitted-by:  Jan Sucan
Dragonfly-bug: <https://bugs.dragonflybsd.org/issues/3044>