staging: comedi: drivers/*.c: add missing braces {} to if/else branches

According to the CodingStyle, braces should  be used on all branches
if thet are used on any branch,

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>