ArmPlatformPkg/PL031RealTimeClockLib: don't clobber gRT table

PL031RealTimeClockLib is a base library that could potentially (although
unlikely) be incorporated into other modules than the DXE_RUNTIME_DRIVER
module that it was intended to complement.

This means the library has no business whatsoever setting the Runtime
Service table pointers directly (since we have no way of knowing which
instance will 'win', and the pointers may end up referring to a module
that is not a DXE_RUNTIME_DRIVER). So remove the assignment altogether.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

ArmPlatformPkg/Library/PL031RealTimeClockLib/PL031RealTimeClockLib.c

@@ -650,12 +650,6 @@ LibRtcInitialize (
     return Status;
   }
 
-  // Setup the setters and getters
-  gRT->GetTime       = LibGetTime;
-  gRT->SetTime       = LibSetTime;
-  gRT->GetWakeupTime = LibGetWakeupTime;
-  gRT->SetWakeupTime = LibSetWakeupTime;
-
   mRT = gRT;
 
   // Install the protocol