staging: comedi: pcmmio: cleanup indent levels in interrupt_pcmmio()

Remove the extra indent levels in this function that resulted from
code removed in previous patches.

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>