Make the mtime for files under /proc be the creation time of the process rather than the boot time.

Notes:
Wed Mar 29 17:42:05 EST 2006 rsc
    This is an interesting idea, but I don't see a use.
    The information is already available in /proc/n/status.  
    Is there a compelling argument to duplicate it?
    Being able to ls -lt /proc doesn't count.
    


Reference: /n/sources/patch/sorry/proc-mtime
Date: Wed Mar 29 13:12:28 CES 2006
Signed-off-by: uriel@cat-v.org
Reviewed-by: rsc

--- /sys/src/9/port/devproc.c	Wed Mar 29 12:52:58 2006
+++ /sys/src/9/port/devproc.c	Wed Mar 29 12:52:53 2006
@@ -225,6 +225,7 @@
 			return -1;
 		mkqid(&qid, (s+1)<<QSHIFT, pid, QTDIR);
 		devdir(c, qid, up->genbuf, 0, p->user, DMDIR|0555, dp);
+		dp->mtime = seconds() - TK2MS(MACHP(0)->ticks - p->time[TReal]) / 1000;
 		return 1;
 	}
 	if(c->qid.path == Qtrace){
@@ -264,6 +265,7 @@
 
 	mkqid(&qid, path|tab->qid.path, c->qid.vers, QTFILE);
 	devdir(c, qid, tab->name, len, p->user, perm, dp);
+	dp->mtime = seconds() - TK2MS(MACHP(0)->ticks - p->time[TReal]) / 1000;
 	return 1;
 }