MdeModulePkg/FirmwarePerformanceDataTableDxe: Remove an unused PCD
    
    The PCD below is unused, so it has been removed from inf.
    gEfiMdeModulePkgTokenSpaceGuid.PcdExtFpdtBootRecordPadSize
    
    Cc: Star Zeng <star.zeng@intel.com>
    Cc: Eric Dong <eric.dong@intel.com>
    Cc: Laszlo Ersek <lersek@redhat.com>
    Contributed-under: TianoCore Contribution Agreement 1.1
    Signed-off-by: shenglei <shenglei.zhang@intel.com>
    Reviewed-by: Star Zeng <star.zeng@intel.com>