ARM: dts: lpc435x: remove address and size cells from gpio-keys-polled nodes

The change removes redundant #address-cells and #size-cells properties from
gpio-keys-polled compatible device nodes found in lpc4357-ea4357-devkit and
lpc4350-hitex-eval board DTS files.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>