ARM: dts: msm: Add SDHC controller nodes for MSM8974 and DB8074 board

Add support for the 2 SDHC controllers on the DB8074 board.  The first
controller (at 0xf9824900) is connected to an on board soldered eMMC.
The second controller (at 0xf98a4900) is connected to a uSD card slot.

Signed-off-by: Georgi Djakov <gdjakov@mm-sol.com>
Signed-off-by: Kumar Gala <galak@codeaurora.org>