dm: sandbox: i2c: Use new emulator parent uclass

Update the device tree, sandbox i2c driver and tests to use the new
emulation parent to hold emulators.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/power/pmic/i2c_pmic_emul.c b/drivers/power/pmic/i2c_pmic_emul.c
index 61fa76a..80efc02 100644
--- a/drivers/power/pmic/i2c_pmic_emul.c
+++ b/drivers/power/pmic/i2c_pmic_emul.c
@@ -104,7 +104,7 @@
 static int sandbox_i2c_pmic_ofdata_to_platdata(struct udevice *emul)
 {
 	struct sandbox_i2c_pmic_plat_data *plat = dev_get_platdata(emul);
-	struct udevice *pmic_dev = dev_get_parent(emul);
+	struct udevice *pmic_dev = i2c_emul_get_device(emul);
 	struct uc_pmic_priv *priv = dev_get_uclass_priv(pmic_dev);
 	const u8 *reg_defaults;