gpio: sim: check the label length when setting up device properties

If the user-space sets the chip label to an empty string - we should
check the length and not override the default name or else line hogs
will not be properly attached.

Fixes: cb8c474e79 ("gpio: sim: new testing module")
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

drivers/gpio/gpio-sim.c

@@ -816,7 +816,7 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 
 	properties[prop_idx++] = PROPERTY_ENTRY_U32("ngpios", bank->num_lines);
 
-	if (bank->label)
+	if (bank->label && (strlen(bank->label) > 0))
 		properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label",
 							       bank->label);