ARM: dts: Fix node status to "okay" on TI boards

ARM: dts: Fix node status to "okay" on TI boards

As per Device Tree Specification [1], the status parameter of nodes can
be "okay", "disabled", etc. "ok" is not a valid parameter.

U-boot Driver Model does not recognize status="ok" either and treats
the node as disabled.

[1] https://github.com/devicetree-org/devicetree-specification/releases/tag/v0.3

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Nishanth Menon <nm@ti.com>