ARM: dts: Add keep-power-in-suspend to WiFi SDIO node for Peach Boards

The Marvell mwifiex driver prevents the system to enter into a suspend
state if the card power is not preserved during a suspend/resume cycle.

So Suspend-to-RAM and Suspend-to-idle is failing on Exynos5800 Peach Pi
and Exynos5420 Peach Pit Chromebooks.

Add the keep-power-in-suspend Power Management property to the SDIO/MMC
node so the mwifiex suspend handler doesn't fail and the system is able
to enter into a suspend state.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>

arch/arm/boot/dts/exynos5420-peach-pit.dts

@@ -711,6 +711,7 @@
 	num-slots = <1>;
 	broken-cd;
 	cap-sdio-irq;
+	keep-power-in-suspend;
 	card-detect-delay = <200>;
 	clock-frequency = <400000000>;
 	samsung,dw-mshc-ciu-div = <1>;

arch/arm/boot/dts/exynos5800-peach-pi.dts

@@ -674,6 +674,7 @@
 	num-slots = <1>;
 	broken-cd;
 	cap-sdio-irq;
+	keep-power-in-suspend;
 	card-detect-delay = <200>;
 	clock-frequency = <400000000>;
 	samsung,dw-mshc-ciu-div = <1>;