ARM: dts: qcom: msm8974-hammerhead: Add sdhci1 node

This introduces the eMMC sdhci node and its pinctrl state

Signed-off-by: Bhushan Shah <bshah@kde.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>