x86: pci-nommu.c cleanup

Impact: cleanup
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>

arch/x86/kernel/pci-nommu.c

 /* Fallback functions when the main IOMMU code is not compiled in. This
    code is roughly equivalent to i386. */
-#include <linux/mm.h>
-#include <linux/init.h>
-#include <linux/pci.h>
-#include <linux/string.h>
 #include <linux/dma-mapping.h>
 #include <linux/scatterlist.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/mm.h>
 
-#include <asm/iommu.h>
 #include <asm/processor.h>
+#include <asm/iommu.h>
 #include <asm/dma.h>
 
 static int