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/lp3971.c b/drivers/regulator/lp3971.c
index 0f22ef1..72b16b5 100644
--- a/drivers/regulator/lp3971.c
+++ b/drivers/regulator/lp3971.c
@@ -16,6 +16,7 @@
 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/lp3971.h>
 #include <linux/slab.h>