regulator: core: Fix cast to pointer from integer of different size warning

This is to address the following warning during compilation time: (Compile on x86_64)

  CC      drivers/regulator/core.o
drivers/regulator/core.c: In function '_regulator_do_set_voltage':
drivers/regulator/core.c:2183:10: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

This patch adds a temporary variable to avoid double cast.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/core.c

@@ -2179,9 +2179,12 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
 		}
 	}
 
-	if (ret == 0 && best_val >= 0)
+	if (ret == 0 && best_val >= 0) {
+		unsigned long data = best_val;
+
 		_notifier_call_chain(rdev, REGULATOR_EVENT_VOLTAGE_CHANGE,
-				     (void *)best_val);
+				     (void *)data);
+	}
 
 	trace_regulator_set_voltage_complete(rdev_get_name(rdev), best_val);