ARM: dts: mba6ulx: Remove unnecessary #address-cells/#size-cells

The following W=1 dtc warning is seen:

arch/arm/boot/dts/mba6ulx.dtsi:33.26-64.4: Warning (avoid_unnecessary_addr_size): /gpio-keys: unnecessary #address-cells/#size-cells without "ranges" or child "reg" property

Remove the unnecessary #address-cells/#size-cells to fix it.

Fixes: 7b8861d8 ("ARM: dts: imx6ul: add TQ-Systems MBa6ULx device trees")
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>