ARM: dts: msm8974pro: Update BW votes to reflect clock plan

Either 931MHz or 800MHz is the turbo BIMC frequency, but both
do not exist in the same build.  Just request 931MHz.

Change-Id: I4b587e08689f9baa6e1088388d2748a298e7c916
Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>