ARM: dts: msm: Add DTS to support eMMC

Add clock, pin control and target specific eMMC support.

Add GPIO configs for DATA Lines 4 to 7 to support in 8 bit mode.

Add eMMC in 8 bit mode as a storage device, not for boot.

Change-Id: Ie3acb7d221c79f55c8b7b5702e56e607aa7eb553
Signed-off-by: Srinivas Ganji <sringanj@codeaurora.org>