ARM: dts: msm: Update SNOC vote to allow SVS on MSM8996

With USB device mode, USB driver votes for nominal SNOC bus frequency
which prevents system going into SVS. This change reduces SNOC vote
from 120 MHz to 100 MHz to allow SVS.

CRs-Fixed: 975648
Change-Id: I13492cddd8af3f9dea4244e24485556c0efac29e
Signed-off-by: Mayank Rana <mrana@codeaurora.org>