ARM: dts: mdm: increase drive strength of CLK line on MDM9630 MTP

Drive strength of CLK line (of SD card slot) is currently set to 10mA
which doesn't seem to be enough for SD card operations (we may see data
timeout/CRC errors occasionally). Increasing the driver strength of CLK
line to 16mA seems to be fixing the isssue hence this change updates the
driver strength to 16mA.

CRs-Fixed: 659152
Change-Id: I12f9efc2fc8800281fdb90ecfde8ded210a49079
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>