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: I6a4245b450a269286d084c78f6977bdcdade0d97
Signed-off-by: Gustavo Solaira <gustavos@codeaurora.org>