regulator: Add module.h to drivers/regulator users as required

Another group of drivers that are taking advantage of the implicit
presence of module.h -- and will break when we pull the carpet out
from under them during a cleanup.  Fix 'em now.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/regulator/ab8500.c b/drivers/regulator/ab8500.c
index 02f3c23..6e1ae69 100644
--- a/drivers/regulator/ab8500.c
+++ b/drivers/regulator/ab8500.c
@@ -13,6 +13,7 @@
  */
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/err.h>
 #include <linux/platform_device.h>
 #include <linux/mfd/ab8500.h>