ARM: dts: msm: Increase size of event ring 6 on msmnile

Event ring 6 of element size 1024 is used for both default 101 and
RSC 104 channels. Both channels are having transfer ring size of 512.
This is usually a problematic configuration where device consumes all
buffers and then writes events and runs out of event ring space in case
host is slow handling events. Fix this situation by increasing event
ring element size from 1024 to 2048.

Change-Id: I7e079b4606d0f1e76ae68b3fcad590e41d953f86
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>