ARM: S5PV210: Fixup ADC device change

Ensure the ADC device is touched only if S3C_DEV_ADC
is selected.

Fixes:
arch/arm/mach-s5pv210/built-in.o: In function `s5pv210_map_io':
/home/kgene/bjdooks/arch/arm/mach-s5pv210/cpu.c:92: undefined reference to `s3c_device_adc'
Signed-off-by: NBen Dooks <ben-linux@fluff.org>

arch/arm/mach-s5pv210/cpu.c

@@ -76,7 +76,9 @@ static void s5pv210_idle(void)
 
 void __init s5pv210_map_io(void)
 {
+#ifdef CONFIG_S3C_DEV_ADC
 	s3c_device_adc.name	= "s3c64xx-adc";
+#endif
 
 	iotable_init(s5pv210_iodesc, ARRAY_SIZE(s5pv210_iodesc));