ARM: dts: msm: Add additional venus vbif settings for apq8084

In order for setting of MMSS_VENUS0_VBIF_ROUND_ROBIN_QOS_ARB to take
affect, _VBIF_REQ_PRIORITY and _VBIF_PRIORITY_LEVEL need to be
programmed beforehand.

Change-Id: I8316e6a3d42f9751843ed03b7377213bf74215c8
Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>