powerpc/83xx: Add a null pointer check to mcu_gpiochip_add

kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure. Ensure the allocation was successful
by checking the pointer validity.

Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20240115094330.33014-1-chentao@kylinos.cn

Author: KunWuChan

arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c

@@ -123,6 +123,8 @@ static int mcu_gpiochip_add(struct mcu *mcu)
 
 	gc->owner = THIS_MODULE;
 	gc->label = kasprintf(GFP_KERNEL, "%pfw", dev_fwnode(dev));
+	if (!gc->label)
+		return -ENOMEM;
 	gc->can_sleep = 1;
 	gc->ngpio = MCU_NUM_GPIO;
 	gc->base = -1;