gpio-amd8111: check ioport_map return value

ioport_map() may fail. Its safe to check the return value.

Signed-off-by: Varka Bhadram <varkab@cdac.in>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-amd8111.c b/drivers/gpio/gpio-amd8111.c
index d3d2d10..2c4d9ab 100644
--- a/drivers/gpio/gpio-amd8111.c
+++ b/drivers/gpio/gpio-amd8111.c
@@ -213,6 +213,11 @@
 		goto out;
 	}
 	gp.pm = ioport_map(gp.pmbase + PMBASE_OFFSET, PMBASE_SIZE);
+	if (!gp.pm) {
+		dev_err(&pdev->dev, "Couldn't map io port into io memory\n");
+		err = -ENOMEM;
+		goto out;
+	}
 	gp.pdev = pdev;
 	gp.chip.dev = &pdev->dev;