Staging: comedi: remove unnecessary braces in pcl711.c

This patch for pcl711.c removes braces causing a checkpatch.pl warning.
It also removes an empty else arm of an if-else statement.

Signed-off-by: Chase Southwood <chase.southwood@yahoo.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>