[ARM] Orion: add a separate BRIDGE_INT_TIMER1_CLR define

Some Feroceon-based SoCs have an MBUS bridge interrupt controller
that requires writing a one instead of a zero to clear edge
interrupt sources such as timer expiry.

This patch adds a new BRIDGE_INT_TIMER1_CLR define, which platform
code can set to either ~BRIDGE_INT_TIMER1 (write-zero-to-clear) or
BRIDGE_INT_TIMER1 (write-one-to-clear) depending on the platform.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
diff --git a/arch/arm/plat-orion/time.c b/arch/arm/plat-orion/time.c
index 28b5285..93c4ef9 100644
--- a/arch/arm/plat-orion/time.c
+++ b/arch/arm/plat-orion/time.c
@@ -74,7 +74,7 @@
 	/*
 	 * Clear and enable clockevent timer interrupt.
 	 */
-	writel(~BRIDGE_INT_TIMER1, BRIDGE_CAUSE);
+	writel(BRIDGE_INT_TIMER1_CLR, BRIDGE_CAUSE);
 
 	u = readl(BRIDGE_MASK);
 	u |= BRIDGE_INT_TIMER1;
@@ -138,7 +138,7 @@
 		/*
 		 * ACK pending timer interrupt.
 		 */
-		writel(~BRIDGE_INT_TIMER1, BRIDGE_CAUSE);
+		writel(BRIDGE_INT_TIMER1_CLR, BRIDGE_CAUSE);
 
 	}
 	local_irq_restore(flags);
@@ -159,7 +159,7 @@
 	/*
 	 * ACK timer interrupt and call event handler.
 	 */
-	writel(~BRIDGE_INT_TIMER1, BRIDGE_CAUSE);
+	writel(BRIDGE_INT_TIMER1_CLR, BRIDGE_CAUSE);
 	orion_clkevt.event_handler(&orion_clkevt);
 
 	return IRQ_HANDLED;