ARM: dts: msm: add device binding for mdmfermium

Add device binding for cnss-sdio driver. The main purpose
of this device binding is to invoke the CNSS SDIO platform
driver. This platform driver adds support for the CNSS
subsystem used for the SDIO based Wi-Fi devices.

CRs-Fixed: 926473
Change-Id: I197d57ad566b6a8357980f6d4d5baa93fef4ebb4
Signed-off-by: Sarada Prasanna Garnayak <sgarna@codeaurora.org>