staging: comedi: don't disable IRQ for comedi_file_info_table_lock

None of the functions that acquire the comedi_file_info_table_lock
spin-lock need to disable interrupts.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>