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 <[e-mail]>
Signed-off-by: Madhavan Srinivasan <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

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

···
 
 	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;