Kernel: Move RTC to Timer directory

PIT ms counter seems to be off by multiple seconds/minute. I will
be probably changing to HPET for system time

kernel/kernel/Input/PS2Keyboard.cpp

@@ -2,6 +2,7 @@
 #include <kernel/CriticalScope.h>
 #include <kernel/FS/DevFS/FileSystem.h>
 #include <kernel/Input/PS2Keyboard.h>
+#include <kernel/Timer/Timer.h>
 
 #include <sys/sysmacros.h>