[ARM] pxa: use chip->ack() instead of accessing GEDR directly

Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
diff --git a/arch/arm/mach-pxa/lpd270.c b/arch/arm/mach-pxa/lpd270.c
index 1373c22..c87abc3 100644
--- a/arch/arm/mach-pxa/lpd270.c
+++ b/arch/arm/mach-pxa/lpd270.c
@@ -121,7 +121,7 @@
 
 	pending = __raw_readw(LPD270_INT_STATUS) & lpd270_irq_enabled;
 	do {
-		GEDR(0) = GPIO_bit(0);  /* clear useless edge notification */
+		desc->chip->ack(irq);	/* clear useless edge notification */
 		if (likely(pending)) {
 			irq = LPD270_IRQ(0) + __ffs(pending);
 			generic_handle_irq(irq);