fix up forgotten bit of conf.nproc (convert to sys->nproc).

Reference: /n/atom/patch/applied2013/nixprocnoconf
Date: Sun Oct 13 21:45:46 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/nix/port/devproc.c	Sun Oct 13 21:45:09 2013
+++ /sys/src/nix/port/devproc.c	Sun Oct 13 21:45:09 2013
@@ -233,7 +233,7 @@
 			if(s < 0)
 				return -1;
 		}
-		else if(s >= conf.nproc)
+		else if(s >= sys->nproc)
 			return -1;
 
 		if((p = psincref(s)) == nil || (pid = p->pid) == 0)
@@ -343,7 +343,7 @@
 static void
 procinit(void)
 {
-	if(conf.nproc >= (SLOTMASK>>QSHIFT) - 1)
+	if(sys->nproc >= (SLOTMASK>>QSHIFT) - 1)
 		print("warning: too many procs for devproc\n");
 	addclock0link((void (*)(void))profclock, 113);	/* Relative prime to HZ */
 }