staging: comedi: addi_apci_1564: split timer and counter subdevices

The timer subdevice is currently broken in this driver.

The Rev 1.0 and 2.x versions of the board both have a 12-bit timer. But only
the Rev 2.x boards have the 3 32-bit counters.

Split the current timer subdevice into two separate subdevices:
  1) A single channel 12-bit timer subdevice
  2) A three channel 32-bit counter subdevice

This represents the hardware correctly and the counters can be disabled on
the Rev 1.0 boards.

Split up the current (*insn_config), (*insn_write), and (*insn_read) so they
only deal with the hardware associated with the subdevice.

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>