MdePkg: Add mipisyst submodule

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4144

This Library provides functions consuming MIPI SYS-T submodule.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Guo Gua <gua.guo@intel.com>
Cc: Chan Laura <laura.chan@intel.com>
Cc: Prakashan Krishnadas Veliyathuparambil <krishnadas.veliyathuparambil.prakashan@intel.com>
Cc: K N Karthik <karthik.k.n@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Michael Kubacki <mikuback@linux.microsoft.com>
Signed-off-by: Guo Gua <gua.guo@intel.com>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Michael Kubacki <mikuback@linux.microsoft.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>

.pytool/CISettings.py

@@ -197,6 +197,8 @@ class Settings(CiBuildSettingsManager, UpdateSettingsManager, SetupSettingsManag
             "UnitTestFrameworkPkg/Library/SubhookLib/subhook", False))
         rs.append(RequiredSubmodule(
             "MdePkg/Library/BaseFdtLib/libfdt", False))
+        rs.append(RequiredSubmodule(
+            "MdePkg/Library/MipiSysTLib/mipisyst", False))
         return rs
 
     def GetName(self):