Display the sum of the runtime of all the threads in a process when it's

multithreaded instead of picking the time of the first thread found.

Reviewed by:	jhb
Approved by:	kan (mentor)
MFC after:	1 month

usr.bin/top/machine.c

@@ -725,6 +725,7 @@ get_process_info(struct system_info *si, struct process_select *sel,
 			prev_pp = pp;
 		} else {
 			prev_pp->ki_pctcpu += pp->ki_pctcpu;
+			prev_pp->ki_runtime += pp->ki_runtime;
 		}
 	}