Kernel: Remove unused header includes in Time subtree

Kernel/Time/APICTimer.cpp

@@ -7,9 +7,7 @@
 #include <Kernel/IO.h>
 #include <Kernel/Interrupts/APIC.h>
 #include <Kernel/Panic.h>
-#include <Kernel/Scheduler.h>
 #include <Kernel/Sections.h>
-#include <Kernel/Thread.h>
 #include <Kernel/Time/APICTimer.h>
 #include <Kernel/Time/TimeManagement.h>
 

Kernel/Time/APICTimer.h

@@ -6,7 +6,6 @@
 
 #pragma once
 
-#include <AK/NonnullRefPtr.h>
 #include <AK/Types.h>
 #include <Kernel/Interrupts/GenericInterruptHandler.h>
 #include <Kernel/Time/HardwareTimer.h>

Kernel/Time/TimeManagement.cpp

@@ -22,7 +22,6 @@
 #include <Kernel/Time/RTC.h>
 #include <Kernel/Time/TimeManagement.h>
 #include <Kernel/TimerQueue.h>
-#include <Kernel/VM/MemoryManager.h>
 
 namespace Kernel {