arm64: dts: qcom: Enable eMMC on apq8016-sbc board

Enable the eMMC on the APQ8016 SBC board (also known as DragonBoard 410c),
so that we can use its internal storage.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Andy Gross <agross@codeaurora.org>