kernel: Keep the old Timer::ticks_ms() API.

Removing this API broke the ATA branch.

kernel/src/arch/Timer.cpp

@@ -62,6 +62,11 @@ namespace Timer
         timespecadd(&s_realtime_clock, &s_interval, &s_realtime_clock);
     }
 
+    usize ticks_ms()
+    {
+        return (s_monotonic_clock.tv_sec * 1000) + (s_monotonic_clock.tv_nsec / 1'000'000);
+    }
+
     struct timespec* monotonic_clock()
     {
         return &s_monotonic_clock;

kernel/src/arch/Timer.h

@@ -16,6 +16,8 @@ namespace Timer
 {
     void tick();
 
+    usize ticks_ms();
+
     struct timespec* monotonic_clock();
 
     struct timespec* realtime_clock();