regulator: Move regulator drivers to subsys_initcall()

Regulators need to be available early in init in order to allow them
to be available for consumers when requested. This is generally done
by registering them at subsys_initcall() time but not all regulator
drivers have done that. Convert these drivers to do so in order to
mimimise future support.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/drivers/regulator/da903x.c b/drivers/regulator/da903x.c
index c6628f5..b8b89ef 100644
--- a/drivers/regulator/da903x.c
+++ b/drivers/regulator/da903x.c
@@ -504,7 +504,7 @@
 {
 	return platform_driver_register(&da903x_regulator_driver);
 }
-module_init(da903x_regulator_init);
+subsys_initcall(da903x_regulator_init);
 
 static void __exit da903x_regulator_exit(void)
 {