ARM: dts: msm: Disable ethernet interface for mhi swip for sdxprairie

Remove "qcom,mhi-ethernet-interface" property such that mhi swip
will support default rawip network interface instead of ethernet
network interface on sdxprairie.

Change-Id: Icb36595c56d44d01cbf0c496fa34ae82e909bc40
Signed-off-by: Aman Gupta <amangupt@codeaurora.org>