staging: comedi: Kconfig: COMEDI_NI_AT_A2150 should select COMEDI_FC

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>
Cc: stable <stable@vger.kernel.org> # 3.6+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/Kconfig

@@ -444,6 +444,7 @@ config COMEDI_ADQ12B
 
 config COMEDI_NI_AT_A2150
 	tristate "NI AT-A2150 ISA card support"
+	select COMEDI_FC
 	depends on VIRT_TO_BUS
 	---help---
 	  Enable support for National Instruments AT-A2150 cards