staging: comedi: pcmuio: remove unnecessary mask of triggered channels

The 'triggered' value is read directly from the three trigger id
registers and does not have any extra data that needs masked off.
Remove the 'mytrig' local variable and just use 'triggered' directly.

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