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

These files were relying on module.h to come in via the path
in an include/acpi header file, but we don't want to have
instances of module.h being included from include/* files
if it can be avoided.  Have the files include export.h instead.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/acpi/debugfs.c b/drivers/acpi/debugfs.c
index 182a9fc..b55d6a2 100644
--- a/drivers/acpi/debugfs.c
+++ b/drivers/acpi/debugfs.c
@@ -2,6 +2,7 @@
  * debugfs.c - ACPI debugfs interface to userspace.
  */
 
+#include <linux/export.h>
 #include <linux/init.h>
 #include <linux/debugfs.h>
 #include <acpi/acpi_drivers.h>