ARM: dts: msm: Modify camera sensor power config for sdm845 rb3 device

- Modify the power config as the schematic for cam-sensor@4 for
  sdm845 rb3 device.
- Change cam-sensor@4 to be cam-sensor@6.

Change-Id: I24df990fd6517cc08488445222f68ce22ac347d6
Signed-off-by: Ziyu Jian <ziyujiang@codeaurora.org>