adc: exynos-adc: Fix wrong bit operation used to stop the ADC

When stopping the ADC_V2_CON1_STC_EN should be cleared.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/drivers/adc/exynos-adc.c b/drivers/adc/exynos-adc.c
index d33e3d6..12c49fc 100644
--- a/drivers/adc/exynos-adc.c
+++ b/drivers/adc/exynos-adc.c
@@ -62,7 +62,7 @@
 
 	/* Stop conversion */
 	cfg = readl(&regs->con1);
-	cfg |= ~ADC_V2_CON1_STC_EN;
+	cfg &= ~ADC_V2_CON1_STC_EN;
 
 	writel(cfg, &regs->con1);