clk: scpi: Fix checking return value of platform_device_register_simple()

platform_device_register_simple() returns ERR_PTR on error.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk-scpi.c

@@ -299,7 +299,7 @@ static int scpi_clocks_probe(struct platform_device *pdev)
 	/* Add the virtual cpufreq device */
 	cpufreq_dev = platform_device_register_simple("scpi-cpufreq",
 						      -1, NULL, 0);
-	if (!cpufreq_dev)
+	if (IS_ERR(cpufreq_dev))
 		pr_warn("unable to register cpufreq device");
 
 	return 0;