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/trace.c b/drivers/base/power/trace.c
index af10abe..d94a1f51 100644
--- a/drivers/base/power/trace.c
+++ b/drivers/base/power/trace.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/resume-trace.h>
+#include <linux/export.h>
 #include <linux/rtc.h>
 
 #include <asm/rtc.h>