ARM: dts: msm: Add dual voltage support for SD card to 8937

Enables dual voltage support for SD card (sdhc2).
This would enable the card to be detected and
operated in SDR104 mode.

Change-Id: I905e9b4f5f93b59b3d35032ee89d117385f0b64c
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>