iio: adc/imx25-gcq: Move incorrect do_div

The newly added driver uses do_div() to device a 32-bit number, which now
provokes a warning:

drivers/iio/adc/fsl-imx25-gcq.c: In function 'mx25_gcq_setup_cfgs':
include/asm-generic/div64.h:207:28: warning: comparison of distinct pointer types lacks a cast
  (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \

This replaces the do_div() call with a straight division operator.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 6df2e98c ("iio: adc: Add imx25-gcq ADC driver")
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/iio/adc/fsl-imx25-gcq.c

@@ -233,7 +233,7 @@ static int mx25_gcq_setup_cfgs(struct platform_device *pdev,
 			priv->channel_vref_mv[reg] =
 				regulator_get_voltage(priv->vref[refp]);
 			/* Conversion from uV to mV */
-			do_div(priv->channel_vref_mv[reg], 1000);
+			priv->channel_vref_mv[reg] /= 1000;
 			break;
 		case MX25_ADC_REFP_INT:
 			priv->channel_vref_mv[reg] = 2500;