MFD: mcp-core: fix complaints from the genirq layer

The genirq layer complains if an interrupt handler returns with
interrupts enabled.  The UCB1x00 handler does just this, because
ucb1x00_enable() calls mcp_enable(), which uses spin_lock_irq()
rather than spin_lock_irqsave().  Convert this, and the divisor
setting functions to use spin_lock_irqsave().
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/mfd/mcp-core.c

@@ -93,9 +93,11 @@ static struct bus_type mcp_bus_type = {
  */
 void mcp_set_telecom_divisor(struct mcp *mcp, unsigned int div)
 {
-	spin_lock_irq(&mcp->lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&mcp->lock, flags);
 	mcp->ops->set_telecom_divisor(mcp, div);
-	spin_unlock_irq(&mcp->lock);
+	spin_unlock_irqrestore(&mcp->lock, flags);
 }
 EXPORT_SYMBOL(mcp_set_telecom_divisor);
 
@@ -108,9 +110,11 @@ EXPORT_SYMBOL(mcp_set_telecom_divisor);
  */
 void mcp_set_audio_divisor(struct mcp *mcp, unsigned int div)
 {
-	spin_lock_irq(&mcp->lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&mcp->lock, flags);
 	mcp->ops->set_audio_divisor(mcp, div);
-	spin_unlock_irq(&mcp->lock);
+	spin_unlock_irqrestore(&mcp->lock, flags);
 }
 EXPORT_SYMBOL(mcp_set_audio_divisor);
 
@@ -163,10 +167,11 @@ EXPORT_SYMBOL(mcp_reg_read);
  */
 void mcp_enable(struct mcp *mcp)
 {
-	spin_lock_irq(&mcp->lock);
+	unsigned long flags;
+	spin_lock_irqsave(&mcp->lock, flags);
 	if (mcp->use_count++ == 0)
 		mcp->ops->enable(mcp);
-	spin_unlock_irq(&mcp->lock);
+	spin_unlock_irqrestore(&mcp->lock, flags);
 }
 EXPORT_SYMBOL(mcp_enable);