ARM: dts: msm: Add sdhc1 and sdhc2 for sdm640-rumi

Add entried for sdhc1(eMMC) and sdhc2(sdcard). But enable only sdhc1 for
now. Enabling SD card without cd-gpio will result in continuous polling.

Change-Id: I5fd71e1d5d177083600e67d46243d5bfa9171b49
Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>