clk: stm32mp1: remove error for disabled clock in stm32mp1_clk_get_parent

To disabled a clock in clock tree initialization for a mux of STM32MP15,
the selected clock source index is set with the latest possible index for
the number of bit used. Today this valid configuration cause a error
in U-Boot messages, for example with CLK_ETH_DISABLED, when this clock
is not needed for the used ETH PHY without crystal:

   no parents defined for clk id 123

This patch change the level of this message to avoid this trace for
valid clock tree.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>

drivers/clk/stm32/clk-stm32mp1.c

@@ -881,7 +881,8 @@ static int stm32mp1_clk_get_parent(struct stm32mp1_clk_priv *priv,
 		return sel[s].parent[p];
 	}
 
-	log_err("no parents defined for clk id %d\n", (u32)id);
+	/* clock is DISABLED when the clock src is not in clk_parent[] range */
+	log_debug("no parents defined for clk id %d\n", (u32)id);
 
 	return -EINVAL;
 }