staging: comedi: amplc_pci230: remove some unnecessary parentheses

Remove some pairs of parentheses that don't really improve readability.
Also, reduce the amount of leading whitespace in a few places.

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