arm: dts: imx: Fix boolean properties with values

Boolean properties in DT are present or not present and don't take a value.
A property such as 'foo = <0>;' evaluated to true. IOW, the value doesn't
matter.

It may have been intended that 0 values are false, but there is no change
in behavior with this patch.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/Yk3mR5yae3gCkKhp@robh.at.kernel.org

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Signed-off-by: Arnd Bergmann <arnd@arndb.de>