SecurityPkg/HashLibTpm2: Fix unused variable usage

I am reliably informed in tianocore#11761
that the correct fix here is not to just remove the unused assignment,
but rather to fix the line following it, which should have been using
the unused value in the way that it now does.

Fixes: tianocore@9c651ef

Signed-off-by: Mike Beaton <[email protected]>

Author: mikebeaton

SecurityPkg/Library/HashLibTpm2/HashLibTpm2PeilessSecLib.c

@@ -586,9 +586,7 @@ HasLibTpm2PeilessSecLibConstructor (
   }
 
   TcgPcrEvent             = (TCG_PCR_EVENT *)EventLog;
-  TcgEfiSpecIdEventStruct = (TCG_EfiSpecIDEventStruct *)
-                            (EventLog + OFFSET_OF (TCG_PCR_EVENT, Event));
-
+  TcgEfiSpecIdEventStruct = (TCG_EfiSpecIDEventStruct *)TcgPcrEvent->Event;
   CopyMem (&NumberOfAlgorithms, TcgEfiSpecIdEventStruct + 1, sizeof (NumberOfAlgorithms));
   DigestSize = (TCG_EfiSpecIdEventAlgorithmSize *)((UINT8 *)TcgEfiSpecIdEventStruct + sizeof (*TcgEfiSpecIdEventStruct) + sizeof (NumberOfAlgorithms));