mips: add export.h to files using EXPORT_SYMBOL/THIS_MODULE

Or else we get lots of variations on this:

arch/mips/pci/pci.c:330: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'

scattered throughout the build.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

arch/mips/powertv/pci/fixup-powertv.c

@@ -1,4 +1,5 @@
 #include <linux/init.h>
+#include <linux/export.h>
 #include <linux/pci.h>
 #include <asm/mach-powertv/interrupts.h>
 #include "powertv-pci.h"

arch/mips/powertv/powertv-usb.c

@@ -29,6 +29,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/export.h>
 #include <linux/ioport.h>
 #include <linux/platform_device.h>
 #include <asm/mach-powertv/asic.h>