ARM: dts: imx6ul-pico-hobbit: Add Wifi support

imx6ul-pico-hobbit has a bcm4343 wifi chip connected to usdhc2 port.

Add support for it.

Signed-off-by: Vanessa Maegima <vanessa.maegima@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>