ARM: dts: msm: add sdhc3 to msm8994

Add device tree nodes and pincontrol for sdhc_3 to the msm8994 device tree.
MSM8994 CDP platform has the option to route the SDC3 slot lines to microSD
card hence this change adds relevant board support for CDP.

Change-Id: Ia1ea1d1c8f83caa9a757c167dab654b0cdb753df
Signed-off-by: Ilia Lin <ilialin@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>