arm64: dts: ipq8074: enable sdhci node

Enable mmc device found on ipq8074 devices

Signed-off-by: Sivaprakash Murugesan <sivaprak@codeaurora.org>
Link: https://lore.kernel.org/r/1591702511-18571-1-git-send-email-sivaprak@codeaurora.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>