arm: tegra: fix error check in tegra2_clocks.c

Checking 'rate < 0' doesn't work because 'rate' is unsigned.
Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Colin Cross <ccross@android.com>

arch/arm/mach-tegra/tegra2_clocks.c

@@ -1362,14 +1362,15 @@ static int tegra_clk_shared_bus_set_rate(struct clk *c, unsigned long rate)
 {
 	unsigned long flags;
 	int ret;
+	long new_rate = rate;
 
-	rate = clk_round_rate(c->parent, rate);
-	if (rate < 0)
-		return rate;
+	new_rate = clk_round_rate(c->parent, new_rate);
+	if (new_rate < 0)
+		return new_rate;
 
 	spin_lock_irqsave(&c->parent->spinlock, flags);
 
-	c->u.shared_bus_user.rate = rate;
+	c->u.shared_bus_user.rate = new_rate;
 	ret = tegra_clk_shared_bus_update(c->parent);
 
 	spin_unlock_irqrestore(&c->parent->spinlock, flags);