ARM: dts: msm: Modify SDHC2 clock rate for msm8939.

Revert SDHC2 clock rate to 200MHz, Which was earlier 177MHz
to avoid data CRC errors observed on SDR104 cards. Those CRC issue
got resolved with commits f81efd12, 29d928 changes in driver.

CRs-fixed:824179
Change-Id: Idc4c20e9efe6f2ac59d03779527bdecb68602a94
Signed-off-by: Pavan Anumula <pavana@codeaurora.org>
Signed-off-by: Bikshapathi Kothapeta <bkotha@codeaurora.org>