ARM: dts: ipq4019: Move xo and timer nodes to SoC dtsi

The node for xo and timer belong to the SoC DTS file.
Else, new board DT files may not inherit these nodes.

Signed-off-by: Varadarajan Narayanan <varada@codeaurora.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>