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/processor_core.c b/drivers/acpi/processor_core.c
index 02d2a4c..3a0428e 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -7,6 +7,7 @@
  *	Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  *	- Added _PDC for platforms with Intel CPUs
  */
+#include <linux/export.h>
 #include <linux/dmi.h>
 #include <linux/slab.h>