If thermal bank with 4 sensors, thermal driver should read TEMP_MSR3.

However, currently thermal driver would not read TEMP_MSR3 since mt8173
thermal driver only use 3 sensors on each thermal bank at the same time,
so this patch would not effect temperature.
Only if mt mt8173 thermal driver use 4 sensors on any thermal bank, would
read third sensor two times, and lose fourth sensor of vale.

Change since V1:
1. Update commis message
 a. Add Reviewed-by: Matthias Brugger [off-list ref]
 b. Add tag Fixes: b7cf0053738c ("thermal: Add Mediatek thermal driver for mt2701.")