UefiCpuPkg/MpLib: fix potential overflow issue.
    
    Current calculate timeout logic may have overflow if the input
    timeout value too large. This patch fix this potential overflow
    issue.
    
    V2: Use local variable instead of call GetPerformanceCounterProperties
    twice. Also correct some comments.
    
    Cc: Michael Kinney <michael.d.kinney@intel.com>
    Cc: Ruiyu Ni <ruiyu.ni@intel.com>
    Contributed-under: TianoCore Contribution Agreement 1.1
    Signed-off-by: Eric Dong <eric.dong@intel.com>
    Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>