clocksource/drivers/imx-tpm: Fix typo of clock name

The clock name should be ipg instead of igp.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/timer-imx-tpm.c

@@ -179,7 +179,7 @@ static int __init tpm_timer_init(struct device_node *np)
 	ipg = of_clk_get_by_name(np, "ipg");
 	per = of_clk_get_by_name(np, "per");
 	if (IS_ERR(ipg) || IS_ERR(per)) {
-		pr_err("tpm: failed to get igp or per clk\n");
+		pr_err("tpm: failed to get ipg or per clk\n");
 		ret = -ENODEV;
 		goto err_clk_get;
 	}