Add input fixed-MTRR MSR index to be start MSR index to avoid finding fixed-MTRR MSR index from 0 at each time. Cc: Feng Tian <feng.tian@intel.com> Cc: Michael Kinney <michael.d.kinney@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jeff Fan <jeff.fan@intel.com> Reviewed-by: Feng Tian <feng.tian@intel.com>