staging: comedi: hwdrv_apci3120: remove forward declarations

This source file is #include'd when building the addi_apci_3001 and
addi_apci_3120 drivers. All the functions in this file are actually
static and should not be exported to the kernel.

Move some of the functions to remove the need for the forward declarations
and make all of the functions in this file static. Note, this patch does
not try to fix any of the coding style issues in the functions.

Also, remove most of the big comment blocks preceding each function.
Leave the 'task' information for some of them to assist in later cleanup.

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