ar71xx: simplify patch 613 and add missing error handling

Dynamic allocation of label can be simplified.
Also add error handling to deal with failed memory allocation.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

SVN-Revision: 49244

target/linux/ar71xx/patches-4.1/613-MIPS-ath79-add-ath79_wmac_setup_ext_lna_gpio-helper.patch

@@ -18,12 +18,12 @@
  
 +static int ath79_request_ext_lna_gpio(unsigned chain, int gpio)
 +{
-+	char buf[32];
 +	char *label;
 +	int err;
 +
-+	scnprintf(buf, sizeof(buf), "external LNA%u", chain);
-+	label = kstrdup(buf, GFP_KERNEL);
++	label = kasprintf(GFP_KERNEL, "external LNA%u", chain);
++	if (!label)
++		return -ENOMEM;
 +
 +	err = gpio_request_one(gpio, GPIOF_DIR_OUT | GPIOF_INIT_LOW, label);
 +	if (err) {

target/linux/ar71xx/patches-4.4/613-MIPS-ath79-add-ath79_wmac_setup_ext_lna_gpio-helper.patch

@@ -18,12 +18,12 @@
  
 +static int ath79_request_ext_lna_gpio(unsigned chain, int gpio)
 +{
-+	char buf[32];
 +	char *label;
 +	int err;
 +
-+	scnprintf(buf, sizeof(buf), "external LNA%u", chain);
-+	label = kstrdup(buf, GFP_KERNEL);
++	label = kasprintf(GFP_KERNEL, "external LNA%u", chain);
++	if (!label)
++		return -ENOMEM;
 +
 +	err = gpio_request_one(gpio, GPIOF_DIR_OUT | GPIOF_INIT_LOW, label);
 +	if (err) {