ARM: dts: ipq8074: Add pcie nodes

The driver/phy support for ipq8074 is available now.
So enabling the nodes in DT.

Reviewed-by: Abhishek Sahu <absahu@codeaurora.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>