Kernel: Add basic HPET support to replace PIT if exists

This works same way as the PIT implementation; calls Scheduler every
milli second.

kernel/CMakeLists.txt

@@ -56,6 +56,7 @@ set(KERNEL_SOURCES
 	kernel/Terminal/TTY.cpp
 	kernel/Terminal/VesaTerminalDriver.cpp
 	kernel/Thread.cpp
+	kernel/Timer/HPET.cpp
 	kernel/Timer/PIT.cpp
 	kernel/Timer/RTC.cpp
 	kernel/Timer/Timer.cpp