imx6: fix pcie interrupt mapping

The interrupt mapping for legacy interrupts was backwards causing interrupts
to be mapped improperly behind a PCIe to PCI bridge (ie GW16082 mezzanine).

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

SVN-Revision: 38519

target/linux/imx6/patches-3.10/0034-PCI-imx6-swizzle-interrupts.patch

@@ -17,10 +17,10 @@ Signed-off-by: Tim Harvey <tharvey@gateworks.com>
  
 -	return pp->irq;
 +	switch (pin) {
-+	case 1: return pp->irq;
-+	case 2: return pp->irq - 1;
-+	case 3: return pp->irq - 2;
-+	case 4: return pp->irq - 3;
++	case 1: return pp->irq - 3;
++	case 2: return pp->irq - 2;
++	case 3: return pp->irq - 1;
++	case 4: return pp->irq;
 +	default: return -1;
 +	}
  }