ARM: dts: msm: Disable IO Cohernecy in trinket fastRPC DT entries

Hardware does not support SMMU IO coherency. Remove
dma-coherent property from fastRPC context bank DT entries.

Change-Id: I1943c7b1ddb83c2df8be8e4410c6b0b836b4810a
Acked-by: Vishnu Karthik D <vikarthi@qti.qualcomm.com>
Signed-off-by: Mohammed Nayeem Ur Rahman <mohara@codeaurora.org>
Signed-off-by: Tharun Kumar Merugu <mtharu@codeaurora.org>