regulator: twl: fix use of integer as pointer

The TWL6030_FIXED_LDO() macro passes the TWL_FIXED_LDO()
macro an 0x0 instead of a NULL. Changing this to a NULL
fixes the following warnings:

drivers/regulator/twl-regulator.c:1068:1: warning: Using plain integer as NULL pointer
drivers/regulator/twl-regulator.c:1069:1: warning: Using plain integer as NULL pointer
drivers/regulator/twl-regulator.c:1070:1: warning: Using plain integer as NULL pointer
drivers/regulator/twl-regulator.c:1071:1: warning: Using plain integer as NULL pointer
drivers/regulator/twl-regulator.c:1072:1: warning: Using plain integer as NULL pointer
drivers/regulator/twl-regulator.c:1073:1: warning: Using plain integer as NULL pointer

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/twl-regulator.c

@@ -905,7 +905,7 @@ static struct regulator_ops twlsmps_ops = {
 			twl4030reg_map_mode)
 #define TWL6030_FIXED_LDO(label, offset, mVolts, turnon_delay) \
 		TWL_FIXED_LDO(label, offset, mVolts, 0x0, turnon_delay, \
-			0x0, TWL6030, twl6030fixed_ops, 0x0)
+			0x0, TWL6030, twl6030fixed_ops, NULL)
 
 #define TWL4030_ADJUSTABLE_LDO(label, offset, num, turnon_delay, remap_conf) \
 static const struct twlreg_info TWL4030_INFO_##label = { \