staging: comedi: addi_apci_3xxx: absorb i_APCI3XXX_InsnWriteAnalogOutput()

Rename this CamelCase function and absorb it from hwdrv_apci3xxx.c
directly into the driver.

Tidy up the analog output subdevice init by adding some whitespace.

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>