regulator: Add module.h include to gpio-regulator

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/gpio-regulator.c

@@ -24,6 +24,7 @@
 
 #include <linux/err.h>
 #include <linux/mutex.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>