ACPI: property: Refactor acpi_data_prop_read_single()

Refactor acpi_data_prop_read_single() for decreased indentation
and better structure. No functional changes intended.

Signed-off-by: Andy Shevchenko <[e-mail]>
Reviewed-by: Sakari Ailus <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/property.c

···
 				      enum dev_prop_type proptype, void *val)
 {
 	const union acpi_object *obj;
-	int ret;
+	int ret = 0;
 
-	if (proptype >= DEV_PROP_U8 && proptype <= DEV_PROP_U64) {
+	if (proptype >= DEV_PROP_U8 && proptype <= DEV_PROP_U64)
 		ret = acpi_data_get_property(data, propname, ACPI_TYPE_INTEGER, &obj);
-		if (ret)
-			return ret;
-
-		switch (proptype) {
-		case DEV_PROP_U8:
-			if (obj->integer.value > U8_MAX)
-				return -EOVERFLOW;
-
-			if (val)
-				*(u8 *)val = obj->integer.value;
-
-			break;
-		case DEV_PROP_U16:
-			if (obj->integer.value > U16_MAX)
-				return -EOVERFLOW;
-
-			if (val)
-				*(u16 *)val = obj->integer.value;
-
-			break;
-		case DEV_PROP_U32:
-			if (obj->integer.value > U32_MAX)
-				return -EOVERFLOW;
-
-			if (val)
-				*(u32 *)val = obj->integer.value;
-
-			break;
-		default:
-			if (val)
-				*(u64 *)val = obj->integer.value;
-
-			break;
-		}
-
-		if (!val)
-			return 1;
-	} else if (proptype == DEV_PROP_STRING) {
+	else if (proptype == DEV_PROP_STRING)
 		ret = acpi_data_get_property(data, propname, ACPI_TYPE_STRING, &obj);
-		if (ret)
-			return ret;
+	if (ret)
+		return ret;
 
+	switch (proptype) {
+	case DEV_PROP_U8:
+		if (obj->integer.value > U8_MAX)
+			return -EOVERFLOW;
+		if (val)
+			*(u8 *)val = obj->integer.value;
+		break;
+	case DEV_PROP_U16:
+		if (obj->integer.value > U16_MAX)
+			return -EOVERFLOW;
+		if (val)
+			*(u16 *)val = obj->integer.value;
+		break;
+	case DEV_PROP_U32:
+		if (obj->integer.value > U32_MAX)
+			return -EOVERFLOW;
+		if (val)
+			*(u32 *)val = obj->integer.value;
+		break;
+	case DEV_PROP_U64:
+		if (val)
+			*(u64 *)val = obj->integer.value;
+		break;
+	case DEV_PROP_STRING:
 		if (val)
 			*(char **)val = obj->string.pointer;
-
 		return 1;
-	} else {
-		ret = -EINVAL;
+	default:
+		return -EINVAL;
 	}
-	return ret;
+
+	/* When no storage provided return number of available values */
+	return val ? 0 : 1;
 }
 
 #define acpi_copy_property_array_uint(items, val, nval)			\