ARM: dts: am43xx: fix cd-gpios definition as per hardware design and dt binding docs

As per mmc device tree binding documentation card detect gpio has
to be active low signal. When a hardware is designed with active
high card detect, gpio polarity has to be changed with
cd-inverted dt property.

In AM43xx the card detect gpio is designed as active low gpio.
So correcting the dt card detect gpio definition.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/dts/am437x-sk-evm.dts b/arch/arm/dts/am437x-sk-evm.dts
index 260edb9..927d8d3 100644
--- a/arch/arm/dts/am437x-sk-evm.dts
+++ b/arch/arm/dts/am437x-sk-evm.dts
@@ -536,7 +536,7 @@
 
 	vmmc-supply = <&dcdc4>;
 	bus-width = <4>;
-	cd-gpios = <&gpio0 6 GPIO_ACTIVE_HIGH>;
+	cd-gpios = <&gpio0 6 GPIO_ACTIVE_LOW>;
 };
 
 &usb2_phy1 {