EmulatorPkg: Use SerialDxe in MdeModulePkg instead of EmbeddedPkg

It is also to add GetControl/SetControl/SetAttributes implementation
for DxeEmuSerialPortLib.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Andrew Fish <afish@apple.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18967 6f19259b-4bc3-4df7-8a09-765794883524