MdePkg: Add SynchronizationLib to MdeLibs.dsc.inc

(cherry picked from commit 4d1f0ba)

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4675

Add library mapping for the SynchronizationLib to MdeLibs.dsc.inc
to resolve build failures in the FmpDevicePkg and NetworkPkg for
missing library mapping.

The following email details why this was missed by EDK II CI

* https://edk2.groups.io/g/devel/message/115185

Local builds of all packages that use -D CONTINUOUS_INTEGRATION
were performed to verify that this change resolves the missing
library mapping.

Cc: Andrew Fish <[email protected]>
Cc: Leif Lindholm <[email protected]>
Cc: Liming Gao <[email protected]>
Cc: Zhiguang Liu <[email protected]>
Cc: Wei6 Xu <[email protected]>
Cc: Saloni Kasbekar <[email protected]>
Cc: Zachary Clark-williams <[email protected]>
Signed-off-by: Michael D Kinney <[email protected]>
Reviewed-by: Leif Lindholm <[email protected]>
(cherry picked from commit 4d1f0ba)

Change-Id: If075ff29bf28410f1082691b37fb8c5480986915

Author: mdkinney

MdePkg/MdeLibs.dsc.inc

@@ -17,3 +17,4 @@
   CpuLib|MdePkg/Library/BaseCpuLib/BaseCpuLib.inf
   SmmCpuRendezvousLib|MdePkg/Library/SmmCpuRendezvousLibNull/SmmCpuRendezvousLibNull.inf
   SafeIntLib|MdePkg/Library/BaseSafeIntLib/BaseSafeIntLib.inf
+  SynchronizationLib|MdePkg/Library/BaseSynchronizationLib/BaseSynchronizationLib.inf