iommu=pt is a valid early param

This avoids a "Malformed early option 'iommu'" warning on boot when 
trying to use pass-through mode.

Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 1a041bc..ae13e34 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -212,10 +212,8 @@
 		if (!strncmp(p, "soft", 4))
 			swiotlb = 1;
 #endif
-		if (!strncmp(p, "pt", 2)) {
+		if (!strncmp(p, "pt", 2))
 			iommu_pass_through = 1;
-			return 1;
-		}
 
 		gart_parse_options(p);