ARM: dts: msm: Add nvmem property in sdhc1 on SDM670

This property will be used to distinguish between different
SoC versions to simplify applying chip version specific
work-arounds.

Change-Id: I561ac0be0e3305a449497354ba3795687a46a2cb
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>