ARM: tegra30: clk: Fix output_rate overflow

Change the type of variable from "unsigned long" to "u64".
This avoids the overflow while clock rate calculating.
Signed-off-by: Mark Zhang <markz@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/mach-tegra/tegra30_clocks.c

@@ -1199,7 +1199,7 @@ static long tegra30_pll_round_rate(struct clk_hw *hw, unsigned long rate,
 {
 	struct clk_tegra *c = to_clk_tegra(hw);
 	unsigned long input_rate = *prate;
-	unsigned long output_rate = *prate;
+	u64 output_rate = *prate;
 	const struct clk_pll_freq_table *sel;
 	struct clk_pll_freq_table cfg;
 	int mul;