lguest: add export.h to lguest files for THIS_MODULE/EXPORT_SYMBOL

We need this in advance of the module.h cleanup, or we'll
get compile errors like this:

  CC      drivers/lguest/lguest_device.o
drivers/lguest/lguest_device.c: In function ‘lguest_devices_init’:
drivers/lguest/lguest_device.c:490: error: ‘THIS_MODULE’ undeclared (first use in this function)

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index f63da5e..cf4603b 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -56,6 +56,7 @@
 #include <linux/lguest_launcher.h>
 #include <linux/virtio_console.h>
 #include <linux/pm.h>
+#include <linux/export.h>
 #include <asm/apic.h>
 #include <asm/lguest.h>
 #include <asm/paravirt.h>