MT#40962 remove 2 ms exemption

Go to sleep even if the sleep time is less than 2 ms. This makes the
math a lot easier and shouldn't have a noticeable impact as this is
a somewhat unnecessary attempt at optimization.

Analogous to 292eb8cf1c

Change-Id: I6d936a4450967dcd76b4647f189aa3f71e5ed7ae

core/sip/wheeltimer.cpp

@@ -84,8 +84,7 @@ void _wheeltimer::run()
       sdiff.tv_sec = diff.tv_sec;
       sdiff.tv_nsec = diff.tv_usec * 1000;
 
-      if(sdiff.tv_nsec > 2000000) // 2 ms 
-	nanosleep(&sdiff,&rem);
+      nanosleep(&sdiff,&rem);
     }
     //else {
     //printf("missed one tick\n");