Staging: comedi: fix numerous brace coding style issues in ni_mio_common.c.

This patch for ni_mio_common.c removes many unneccesary braces to fix
checkpatch.pl warnings.
Signed-off-by: Chase Southwood <chase.southwood@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>