staging: comedi: addi_apci_1032: cleanup i_APCI1032_ReadMoreDigitalInput()

Move this function from hwdrv_apci1032.c.

Remove the unnecessary comment and rename the CamelCase function to
apci1032_di_insn_bits().

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>