BeagleBoardPkg: Ensure there is no pending IRQ and disable timer

When the BeagleBoard UEFI is started from a 1st (or 2nd stage) boot loader
it is possible there are still some pending IRQ.
Clean the interrupts before starting the BeagleBoard UEFI.



git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12034 6f19259b-4bc3-4df7-8a09-765794883524

Omap35xxPkg/TimerDxe/Timer.c

@@ -356,6 +356,9 @@ TimerInitialize (
   Status = gInterrupt->RegisterInterruptSource (gInterrupt, gVector, TimerInterruptHandler);
   ASSERT_EFI_ERROR (Status);
 
+  // Turn on the functional clock for Timer
+  MmioOr32 (CM_FCLKEN_PER, CM_FCLKEN_PER_EN_GPT3_ENABLE);
+
   // Set up default timer
   Status = TimerDriverSetTimerPeriod (&gTimer, FixedPcdGet32(PcdTimerPeriod));
   ASSERT_EFI_ERROR (Status);