regulator: max77857: Fix Wvoid-pointer-to-enum-cast warning

'id' is an enum, thus cast of pointer on 64-bit compile test with W=1
causes:

  max77857-regulator.c:56:24: error: cast to smaller integer type 'enum max77857_id' from 'void *' [-Werror,-Wvoid-pointer-to-enum-cast]

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230810111914.204847-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: krzk

drivers/regulator/max77857-regulator.c

@@ -53,7 +53,7 @@ enum max77857_id {
 
 static bool max77857_volatile_reg(struct device *dev, unsigned int reg)
 {
-	enum max77857_id id = (enum max77857_id)dev_get_drvdata(dev);
+	enum max77857_id id = (uintptr_t)dev_get_drvdata(dev);
 
 	switch (id) {
 	case ID_MAX77831:
@@ -91,7 +91,7 @@ static int max77857_get_status(struct regulator_dev *rdev)
 
 static unsigned int max77857_get_mode(struct regulator_dev *rdev)
 {
-	enum max77857_id id = (enum max77857_id)rdev_get_drvdata(rdev);
+	enum max77857_id id = (uintptr_t)rdev_get_drvdata(rdev);
 	unsigned int regval;
 	int ret;
 
@@ -125,7 +125,7 @@ static unsigned int max77857_get_mode(struct regulator_dev *rdev)
 
 static int max77857_set_mode(struct regulator_dev *rdev, unsigned int mode)
 {
-	enum max77857_id id = (enum max77857_id)rdev_get_drvdata(rdev);
+	enum max77857_id id = (uintptr_t)rdev_get_drvdata(rdev);
 	unsigned int reg, val;
 
 	switch (id) {