Revert "gpio: Restrict usage of GPIO chip irq members before initialization"

This reverts commit 0912cf021f.

It breaks the kernel abi so revert it for now.  We will add it back
later at the next kabi update.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ic05524e1d76a349bf55d12d3b571114483ed7d1b

drivers/gpio/gpiolib.c

@@ -1368,16 +1368,6 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset)
 {
 	struct irq_domain *domain = gc->irq.domain;
 
-#ifdef CONFIG_GPIOLIB_IRQCHIP
-	/*
-	 * Avoid race condition with other code, which tries to lookup
-	 * an IRQ before the irqchip has been properly registered,
-	 * i.e. while gpiochip is still being brought up.
-	 */
-	if (!gc->irq.initialized)
-		return -EPROBE_DEFER;
-#endif
-
 	if (!gpiochip_irqchip_irq_valid(gc, offset))
 		return -ENXIO;
 
@@ -1562,15 +1552,6 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
 
 	acpi_gpiochip_request_interrupts(gc);
 
-	/*
-	 * Using barrier() here to prevent compiler from reordering
-	 * gc->irq.initialized before initialization of above
-	 * GPIO chip irq members.
-	 */
-	barrier();
-
-	gc->irq.initialized = true;
-
 	return 0;
 }
 

include/linux/gpio/driver.h

@@ -224,15 +224,6 @@ struct gpio_irq_chip {
 				unsigned long *valid_mask,
 				unsigned int ngpios);
 
-	/**
-	 * @initialized:
-	 *
-	 * Flag to track GPIO chip irq member's initialization.
-	 * This flag will make sure GPIO chip irq members are not used
-	 * before they are initialized.
-	 */
-	bool initialized;
-
 	/**
 	 * @valid_mask:
 	 *