clk: mediatek: clk-mt7629-eth: Add check for mtk_alloc_clk_data

Add the check for the return value of mtk_alloc_clk_data() in order to
avoid NULL pointer dereference.

Fixes: 3b5e748615e7 ("clk: mediatek: add clock support for MT7629 SoC")
Signed-off-by: Jiasheng Jiang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/mediatek/clk-mt7629-eth.c

···
 	int r;
 
 	clk_data = mtk_alloc_clk_data(CLK_ETH_NR_CLK);
+	if (!clk_data)
+		return -ENOMEM;
 
 	mtk_clk_register_gates(&pdev->dev, node, eth_clks,
 			       CLK_ETH_NR_CLK, clk_data);
···
 	int r;
 
 	clk_data = mtk_alloc_clk_data(CLK_SGMII_NR_CLK);
+	if (!clk_data)
+		return -ENOMEM;
 
 	mtk_clk_register_gates(&pdev->dev, node, sgmii_clks[id++],
 			       CLK_SGMII_NR_CLK, clk_data);