arm: dts: include gpio nodes for card detect

Several MMC drivers use GPIO for card detection with cd-gpios property in
the MMC node pointing to a GPIO node. However, as U-Boot tries to save
space by keeping only required nodes using u-boot* properties, several
devices tree result in having only in the MMC node but not the GPIO node
associated to cd-gpios.

This patch, fixes several ocurrence of this issue.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Adam Ford <aford173@gmail.com> #da850-evm
diff --git a/arch/arm/dts/da850-evm-u-boot.dtsi b/arch/arm/dts/da850-evm-u-boot.dtsi
index d9afc5e..d588628 100644
--- a/arch/arm/dts/da850-evm-u-boot.dtsi
+++ b/arch/arm/dts/da850-evm-u-boot.dtsi
@@ -39,3 +39,7 @@
 &spi1 {
 	u-boot,dm-spl;
 };
+
+&gpio {
+	u-boot,dm-spl;
+};