[ARM] pxa/csb726: adjust duplicate structure field initialization

Currently the irq_type field of the csb726_lan_config structure is
initialized twice.  The value in the first case,
SMSC911X_IRQ_POLARITY_ACTIVE_LOW, is normally stored in the irq_polarity
field, so I have renamed the field in the first initialization to that.
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NEric Miao <eric.y.miao@gmail.com>

arch/arm/mach-pxa/csb726.c

@@ -238,7 +238,7 @@ static struct resource csb726_lan_resources[] = {
 };
 
 struct smsc911x_platform_config csb726_lan_config = {
-	.irq_type	= SMSC911X_IRQ_POLARITY_ACTIVE_LOW,
+	.irq_polarity	= SMSC911X_IRQ_POLARITY_ACTIVE_LOW,
 	.irq_type	= SMSC911X_IRQ_TYPE_PUSH_PULL,
 	.flags		= SMSC911X_USE_32BIT,
 	.phy_interface	= PHY_INTERFACE_MODE_MII,