cam-service: Add clock tolerance to mitigate real-time clock drift

This commit introduces a configurable clock tolerance value to
address real-time clock differences between the server and client.
The adjustment helps reduce drift and ensures improved
synchronization.This tolerance allows for fine-tuning the clock
synchronization and helps reduce drift. The default value for the
tolerance is set to 0 nanoseconds.

Signed-off-by: Divin Raj <divin.raj@arm.com>