Generic sleep_micro() function

kernel/amd64/time.c

@@ -0,0 +1,7 @@
+#include <libk/std.h>
+#include <sys/time.h>
+#include <amd64/hpet.h>
+
+void sleep_micro (size_t us) {
+  amd64_hpet_sleep_micro (us);
+}