clk: imx6ul: fix "failed to get parent" error

On some configuration we may get following error:
[    0.000000] imx:clk-gpr-mux: failed to get parent (-EINVAL)

This happens if selector is configured to not supported value. To avoid
this warnings add dummy parents for not supported values.

Fixes: 4e197ee ("clk: imx6ul: add ethernet refclock mux support")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20230310164523.534571-1-o.rempel@pengutronix.de
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/imx/clk-imx6ul.c

@@ -95,14 +95,16 @@ static const struct clk_div_table video_div_table[] = {
 	{ }
 };
 
-static const char * enet1_ref_sels[] = { "enet1_ref_125m", "enet1_ref_pad", };
+static const char * enet1_ref_sels[] = { "enet1_ref_125m", "enet1_ref_pad", "dummy", "dummy"};
 static const u32 enet1_ref_sels_table[] = { IMX6UL_GPR1_ENET1_TX_CLK_DIR,
-					    IMX6UL_GPR1_ENET1_CLK_SEL };
+					    IMX6UL_GPR1_ENET1_CLK_SEL, 0,
+					    IMX6UL_GPR1_ENET1_TX_CLK_DIR | IMX6UL_GPR1_ENET1_CLK_SEL };
 static const u32 enet1_ref_sels_table_mask = IMX6UL_GPR1_ENET1_TX_CLK_DIR |
 					     IMX6UL_GPR1_ENET1_CLK_SEL;
-static const char * enet2_ref_sels[] = { "enet2_ref_125m", "enet2_ref_pad", };
+static const char * enet2_ref_sels[] = { "enet2_ref_125m", "enet2_ref_pad", "dummy", "dummy"};
 static const u32 enet2_ref_sels_table[] = { IMX6UL_GPR1_ENET2_TX_CLK_DIR,
-					    IMX6UL_GPR1_ENET2_CLK_SEL };
+					    IMX6UL_GPR1_ENET2_CLK_SEL, 0,
+					    IMX6UL_GPR1_ENET2_TX_CLK_DIR | IMX6UL_GPR1_ENET2_CLK_SEL };
 static const u32 enet2_ref_sels_table_mask = IMX6UL_GPR1_ENET2_TX_CLK_DIR |
 					     IMX6UL_GPR1_ENET2_CLK_SEL;