PcAtChipsetPkg PeiAcpiTimerLib: Add the missing DebugLib header file

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Liming Gao <liming.gao@intel.com>
(cherry picked from commit 8ee7ad9)

PcAtChipsetPkg/Library/AcpiTimerLib/PeiAcpiTimerLib.c

@@ -16,6 +16,7 @@
 #include <Library/TimerLib.h>
 #include <Library/BaseLib.h>
 #include <Library/HobLib.h>
+#include <Library/DebugLib.h>
 
 extern GUID mFrequencyHobGuid;