staging: comedi: me4000: convert driver to use the comedi_8254 module

staging: comedi: me4000: convert driver to use the comedi_8254 module

Some of the hardware supported by this driver include an 8254 timer. For
aesthetics, convert it to use the comedi_8254 module to provide support for
the 8254 timer.

This also fixes the (*insn_read) and (*insn_write) to work like the comedi
API expects. Currently they only read or write a single value.

It also fixes the (*insn_config). Currently the driver is attempting to
handle the configuration instructions GPCT_RESET and GPCT_SET_OPERATION.
These are just arbitrary valuse and are not real comedi configuration_ids.
They actually coorespond to:

  GPCT_RESET -> INSN_CONFIG_DIO_OUTPUT
  GPCT_SET_OPERATION -> INSN_CONFIG_ANALOG_TRIG

The number of parameters for the instructions is validated by the comedi
core in check_insn_config_length(). GPCT_RESET happens to work (insn->n == 1)
but GPCT_SET_OPERATION would fail. The INSN_CONFIG_ANALOG_TRIG expects
insn->n == 5 but GPCT_SET_OPERATION in this driver expects insn->n == 2.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>