fix uninitialized warning.  i variable is always initialized since i==100
and since i==100, ot is initialized.

Reference: /n/atom/patch/applied/rtcredux
Date: Sat Mar  1 16:42:28 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/9/pc/devrtc.c	Sat Mar  1 16:41:39 2014
+++ /sys/src/9/pc/devrtc.c	Sat Mar  1 16:41:40 2014
@@ -159,6 +159,7 @@
 	ilock(&nvrtlock);
 
 	/* loop till we get two reads in a row the same */
+	ot = 0;
 	t = _rtctime();
 	for(i = 0; i < 100; i++){
 		ot = t;
--- /sys/src/9/pcpae/devrtc.c	Sat Mar  1 16:41:41 2014
+++ /sys/src/9/pcpae/devrtc.c	Sat Mar  1 16:41:42 2014
@@ -159,6 +159,7 @@
 	ilock(&nvrtlock);
 
 	/* loop till we get two reads in a row the same */
+	ot = 0;
 	t = _rtctime();
 	for(i = 0; i < 100; i++){
 		ot = t;
--- /sys/src/nix/k10/devrtc.c	Sat Mar  1 16:41:44 2014
+++ /sys/src/nix/k10/devrtc.c	Sat Mar  1 16:41:44 2014
@@ -159,6 +159,7 @@
 	ilock(&nvrtlock);
 
 	/* loop till we get two reads in a row the same */
+	ot = 0;
 	t = rtcextract();
 	for(i = 0; i < 100; i++){
 		ot = rtcextract();
@@ -220,7 +221,7 @@
 #define PUTBCD(n,o) bcdclock[o] = (n % 10) | (((n / 10) % 10)<<4)
 
 static long	 
-rtcwrite(Chan* c, void* buf, long n, vlong off)
+rtcwrite(Chan* c, void* buf, long n, vlong offset)
 {
 	int t;
 	char *a, *start;
@@ -228,13 +229,11 @@
 	ulong secs;
 	uchar bcdclock[Nbcd];
 	char *cp, *ep;
-	ulong offset = off;
 
 	if(offset!=0)
 		error(Ebadarg);
 
-
-	switch((ulong)c->qid.path){
+	switch((uint)c->qid.path){
 	case Qrtc:
 		/*
 		 *  read the time