clk: check parent device UCLASS_CLK before retrieving clock pointer

Ensure the parent device is checked for UCLASS_CLK before retrieving its
clock pointer.
This fixes missing clocks in the clock dump caused by invalid parent
devices.

Change-Id: I2ada1510230dcacf6bfb924165fd18a3d48ae0f9
Signed-off-by: Gabriel FERNANDEZ <gabriel.fernandez@st.com>
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/u-boot/+/516402
Tested-by: Gabriel FERNANDEZ <gabriel.fernandez@foss.st.com>
ACI: CITOOLS <MDG-smet-aci-reviews@list.st.com>
ACI: CIBUILD <MDG-smet-aci-builds@list.st.com>
Reviewed-by: Patrice CHOTARD <patrice.chotard@foss.st.com>
Domain-Review: Patrick DELAUNAY <patrick.delaunay@foss.st.com>
Reviewed-by: Gabriel FERNANDEZ <gabriel.fernandez@foss.st.com>

Author: Gabriel-Fernandez-stm

drivers/clk/clk-uclass.c

@@ -506,6 +506,10 @@ struct clk *clk_get_parent(struct clk *clk)
 	pdev = dev_get_parent(clk->dev);
 	if (!pdev)
 		return ERR_PTR(-ENODEV);
+
+	if (device_get_uclass_id(pdev) != UCLASS_CLK)
+		return ERR_PTR(-ENODEV);
+
 	pclk = dev_get_clk_ptr(pdev);
 	if (!pclk)
 		return ERR_PTR(-ENODEV);