ARM: dts: wandboard: Add support for SDIO bcm4329

The wandboard has a Broadcom 4329 WiFi connected via SDIO. This patch
sets the required pins to enable the wifi module.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>