mfd: Fix jz4740_adc_set_enabled

When enabled is false, clear BIT(engine) of JZ_REG_ADC_ENABLE register.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/jz4740-adc.c b/drivers/mfd/jz4740-adc.c
index 3ad492c..9dd1b33 100644
--- a/drivers/mfd/jz4740-adc.c
+++ b/drivers/mfd/jz4740-adc.c
@@ -153,7 +153,7 @@
 	if (enabled)
 		val |= BIT(engine);
 	else
-		val &= BIT(engine);
+		val &= ~BIT(engine);
 	writeb(val, adc->base + JZ_REG_ADC_ENABLE);
 
 	spin_unlock_irqrestore(&adc->lock, flags);