Fix -Wformat-security issue

An extra set of parens is likely not what this line intended to do.
This was caught by -Wformat-security flags.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I4553cdc1b1f6ecda85b0a0a17b2bac8c9e5ae1c6
diff --git a/libopenbmc_intf/gpio.c b/libopenbmc_intf/gpio.c
index afa0914..0226ced 100644
--- a/libopenbmc_intf/gpio.c
+++ b/libopenbmc_intf/gpio.c
@@ -174,7 +174,7 @@
 	size_t len = strlen(gpio);
 	if (len < 2)
 	{
-		fprintf(stderr, ("Invalid GPIO name %s\n", gpio));
+		fprintf(stderr, "Invalid GPIO name %s\n", gpio);
 		return -1;
 	}