Rearrange endpoint number layout

The constants ANY, NONE, and SELF are now a function of the way the
endpoint number is split between a generation number and a process
slot number, rather than the other way around.  This allows for the
use of bit masking and shifting instead of the previous (and more
expensive) multiplication and division.

Change-Id: Id890eea74435444128c75eb0c89816b948f43c0b

test/test39.c

@@ -23,7 +23,7 @@ void test39a()
   subtest = 1;
 
   for (g = 0; g <= _ENDPOINT_MAX_GENERATION; g++) {
-	for (p = -MAX_NR_TASKS; p < _NR_PROCS; p++) {
+	for (p = -MAX_NR_TASKS; p < MAX_NR_PROCS; p++) {
 		endpoint_t ept;
 		int mg, mp;
 		ept = _ENDPOINT(g, p);