ARM: dts: vfxxx: Correctly use two tuples for timer address

Address and size-cells are 1 and the ftm timer node takes two address
spaces in "reg" property, so this should be in two <> tuples.  Change
has no functional impact, but original code is confusing/less readable.

Fixes: 07513e13 ("ARM: dts: vf610: Add Freescale FlexTimer Module timer node.")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>