Copy MdeModulePkg/Library/BaseSerialPortLib16550 revision 89ecd4cf8078aa946083cdcbf9af81ff29f8d9f5. Change-Id: Ie2fd0123bdd7aaba4335afdb1cb017f3690455c6 Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com> Reviewed-by: Prince Agyeman <prince.agyeman@intel.com>