The 'ni_at_a2150' module links to `cfc_write_to_buffer` in the
'comedi_fc' module, so selecting 'COMEDI_NI_AT_A2150' in the kernel config
needs to also select 'COMEDI_FC'.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>