sunxi: axp152: dcdc3 scale is 50mV / step not 25mV / step

Currently uboot wrongly uses 25mV / step for dcdc3, this is a copy and paste
error introduced when adding the axp152_mvolt_to_target during review of the
axp152.c driver. This results in u-boot setting Vddr to 2.3V instead of 1.5V.

This commit fixes this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/drivers/power/axp152.c b/drivers/power/axp152.c
index fa4ea05..27c2c4c 100644
--- a/drivers/power/axp152.c
+++ b/drivers/power/axp152.c
@@ -62,7 +62,7 @@
 
 int axp152_set_dcdc3(int mvolt)
 {
-	u8 target = axp152_mvolt_to_target(mvolt, 700, 3500, 25);
+	u8 target = axp152_mvolt_to_target(mvolt, 700, 3500, 50);
 
 	return axp152_write(AXP152_DCDC3_VOLTAGE, target);
 }