IntelFspPkg: Update BaseFspDebugLibSerialPort library
    
    Implement new API DebugPrintLevelEnabled() to base on PCD PcdFixedDebugPrintErrorLevel.
    
    Contributed-under: TianoCore Contribution Agreement 1.0
    Signed-off-by: Liming Gao <liming.gao@intel.com>
    Reviewed-by: Star Zeng <star.zeng@intel.com>
    
    git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16795 6f19259b-4bc3-4df7-8a09-765794883524