pinctrl: mcp23s08: Improve unlocking of a mutex in mcp23s08_irq()

* Add a jump target so that a call of the function "mutex_unlock" is stored
  only twice in this function implementation.

* Replace five calls by goto statements.

* Adjust five condition checks.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-mcp23s08.c

@@ -455,31 +455,22 @@ static irqreturn_t mcp23s08_irq(int irq, void *data)
 		defval_changed, gpio_set;
 
 	mutex_lock(&mcp->lock);
-	if (mcp_read(mcp, MCP_INTF, &intf) < 0) {
-		mutex_unlock(&mcp->lock);
-		return IRQ_HANDLED;
-	}
+	if (mcp_read(mcp, MCP_INTF, &intf))
+		goto unlock;
 
-	if (mcp_read(mcp, MCP_INTCAP, &intcap) < 0) {
-		mutex_unlock(&mcp->lock);
-		return IRQ_HANDLED;
-	}
+	if (mcp_read(mcp, MCP_INTCAP, &intcap))
+		goto unlock;
 
-	if (mcp_read(mcp, MCP_INTCON, &intcon) < 0) {
-		mutex_unlock(&mcp->lock);
-		return IRQ_HANDLED;
-	}
+	if (mcp_read(mcp, MCP_INTCON, &intcon))
+		goto unlock;
 
-	if (mcp_read(mcp, MCP_DEFVAL, &defval) < 0) {
-		mutex_unlock(&mcp->lock);
-		return IRQ_HANDLED;
-	}
+	if (mcp_read(mcp, MCP_DEFVAL, &defval))
+		goto unlock;
 
 	/* This clears the interrupt(configurable on S18) */
-	if (mcp_read(mcp, MCP_GPIO, &gpio) < 0) {
-		mutex_unlock(&mcp->lock);
-		return IRQ_HANDLED;
-	}
+	if (mcp_read(mcp, MCP_GPIO, &gpio))
+		goto unlock;
+
 	gpio_orig = mcp->cached_gpio;
 	mcp->cached_gpio = gpio;
 	mutex_unlock(&mcp->lock);
@@ -541,6 +532,10 @@ static irqreturn_t mcp23s08_irq(int irq, void *data)
 	}
 
 	return IRQ_HANDLED;
+
+unlock:
+	mutex_unlock(&mcp->lock);
+	return IRQ_HANDLED;
 }
 
 static void mcp23s08_irq_mask(struct irq_data *data)