ARM: dts: msm: Increase camnoc bw margin for sm8150

Increase camnoc axi bandwidth margin from 10 to 20.
Based on camnoc bus efficiency analysis, the suggested
bw margin value is 20.

Change-Id: Ic39cf937074fb11b6bc82e3cd683f707bf6b4bf0
Signed-off-by: Pavan Kumar Chilamkurthi <pchilamk@codeaurora.org>