ARM: dts: am3517: Fix pinmuxing for CD on MMC1

The MMC1 is active low, not active high.  For some reason,
this worked with different combination of U-Boot and kernels,
but it's supposed to be active low and is currently broken.

Fixes: cfaa856a ("ARM: dts: am3517: Add pinmuxing, CD and
WP for MMC1") #kernel 4.18+
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am3517-evm.dts

@@ -228,7 +228,7 @@ &mmc1 {
 	vmmc-supply = <&vmmc_fixed>;
 	bus-width = <4>;
 	wp-gpios = <&gpio4 30 GPIO_ACTIVE_HIGH>; /* gpio_126 */
-	cd-gpios = <&gpio4 31 GPIO_ACTIVE_HIGH>; /* gpio_127 */
+	cd-gpios = <&gpio4 31 GPIO_ACTIVE_LOW>; /* gpio_127 */
 };
 
 &mmc3 {