[Consensus] Bury segwit deployment

Hardcode segwit deployment height to 481824 for mainnet.

src/versionbitsinfo.cpp

@@ -11,8 +11,4 @@ const struct VBDeploymentInfo VersionBitsDeploymentInfo[Consensus::MAX_VERSION_B
         /*.name =*/ "testdummy",
         /*.gbt_force =*/ true,
     },
-    {
-        /*.name =*/ "segwit",
-        /*.gbt_force =*/ true,
-    }
 };