staging: comedi: adl_pci9111: fix alignment issue

Use a local variable for the 'devpriv->ai_bounce_buffer' to shorten
the lines in pci9111_handle_fifo_half_full() and gix the checkpath.pl
issue about:

CHECK: Alignment should match open parenthesis

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>