staging: comedi: adl_pci9118: all registers are 32-bit

According to the PCI-9118 User's Manual, all registers are 32-bit. Fix a
couple of read/write operations that use 16-bit access.

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>