ARM: dts: msm: Remove unused IPA/GSI value

BAM support was removed from IPA3 driver, so GSI is the only possible
transport. Thus don't need to specify a transport in the dtsi file.

Change-Id: I3eae8709e6718a16339dc91cf522ced7889c2c74
Acked-by: Dmitry Kogan <dmitryk@qti.qualcomm.com>
Signed-off-by: Amir Levy <alevy@codeaurora.org>