ARM: cleanup: clk_get_sys() error handling

Fix clk_get_sys() error handling; IS_ERR() should be used rather than
IS_ERR_OR_NULL() to check for errors.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-tegra/tegra2_emc.c b/arch/arm/mach-tegra/tegra2_emc.c
index e18aa2f..03e742f 100644
--- a/arch/arm/mach-tegra/tegra2_emc.c
+++ b/arch/arm/mach-tegra/tegra2_emc.c
@@ -276,7 +276,7 @@
 	int i;
 
 	WARN_ON(pdev->dev.platform_data);
-	BUG_ON(IS_ERR_OR_NULL(c));
+	BUG_ON(IS_ERR(c));
 
 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 	pdata->tables = devm_kzalloc(&pdev->dev, sizeof(*pdata->tables),