drivers/base: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required.

Most of these files were implicitly getting EXPORT_SYMBOL via
device.h which was including module.h, but that path will be broken
soon.

[ with input from Stephen Rothwell <sfr@canb.auug.org.au> ]

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 14ee07e..caf995f 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -10,6 +10,7 @@
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/capability.h>
+#include <linux/export.h>
 #include <linux/suspend.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>