ARM: dts: imx6q-bx50v3: user-space watchdog GPIO configuration

Leave b{4,6}50v3 GPIO expander pca953x pins P05,P10,P11 unconfigured as
they are now used to implement an additional watchdog mechanism in user
space.  P10,P11 pins remain unused (and therefore hogged) on b850v3.

Signed-off-by: Ian Ray <ian.ray@ge.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>