ARM: shmobile: r7s72100: fix bus clock calculation

The picture in the datasheet is a little misleading, yet the divider of
the bus_clk is 1/3 and not 2/3.
Signed-off-by: Wolfram Sang <wsa@sang-engineering.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/clock-r7s72100.c

@@ -70,7 +70,7 @@ static struct clk pll_clk = {
 
 static unsigned long bus_recalc(struct clk *clk)
 {
-	return clk->parent->rate * 2 / 3;
+	return clk->parent->rate / 3;
 }
 
 static struct sh_clk_ops bus_clk_ops = {