ARM: OMAP1: ams-delta-fiq: Fix missing irq_ack

Non-serio path of Amstrad Delta FIQ deferred handler depended on
irq_ack() method provided by OMAP GPIO driver.  That method has been
removed by commit 693de831 ("gpio: omap: remove irq_ack method").
Remove useless code from the deferred handler and reimplement the
missing operation inside the base FIQ handler.

Should another dependency - irq_unmask() - be ever removed from the OMAP
GPIO driver, WARN once if missing.
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap1/ams-delta-fiq-handler.S

@@ -129,6 +129,8 @@ restart:
 	orr r11, r11, r13			@ mask all requested interrupts
 	str r11, [r12, #OMAP1510_GPIO_INT_MASK]
 
+	str r13, [r12, #OMAP1510_GPIO_INT_STATUS] @ ack all requested interrupts
+
 	ands r10, r13, #KEYBRD_CLK_MASK		@ extract keyboard status - set?
 	beq hksw				@ no - try next source
 
@@ -136,7 +138,6 @@ restart:
 	@@@@@@@@@@@@@@@@@@@@@@
 	@ Keyboard clock FIQ mode interrupt handler
 	@ r10 now contains KEYBRD_CLK_MASK, use it
-	str r10, [r12, #OMAP1510_GPIO_INT_STATUS]	@ ack the interrupt
 	bic r11, r11, r10				@ unmask it
 	str r11, [r12, #OMAP1510_GPIO_INT_MASK]
 

arch/arm/mach-omap1/ams-delta-fiq.c

@@ -72,9 +72,7 @@ static irqreturn_t deferred_fiq(int irq, void *dev_id)
 			 * interrupts default to since commit 80ac93c27441
 			 * requires interrupt already acked and unmasked.
 			 */
-			if (irq_chip->irq_ack)
-				irq_chip->irq_ack(d);
-			if (irq_chip->irq_unmask)
+			if (!WARN_ON_ONCE(!irq_chip->irq_unmask))
 				irq_chip->irq_unmask(d);
 		}
 		for (; irq_counter[gpio] < fiq_count; irq_counter[gpio]++)