wandboard_defconfig: add CONFIG_FHANDLE

CONFIG_FHANDLE is needed to use systemd
wandboard_defconfig: add CONFIG_SLUB_DEBUG
ARM i.MX6 Wandboard add wifi+bt rfkill driver

BRCM WiFi module requires initialization for control gpio;
Additional provides rfkill funcs.

v2: fix wrong probe func in driver struct
v3: add imx6qdl compatible

Signed-off-by: Vladimir Ermakov <vooon341@gmail.com>
Signed-off-by: John Weber <rjohnweber@gmail.com>
wandboard: dts fixes
wandboard_defconfig:  Enable RFKILL
wandboard: Cleanup dts

Remove unnecessary comments, experimental functions, and unsupported
functions such as CEC.