clk: sunxi: sun9i-mmc: check return value after calling platform_get_resource()

It will cause null-ptr-deref if platform_get_resource() returns NULL,
we need check the return value.

Fixes: 7a6fca8 ("clk: sunxi: Add driver for A80 MMC config clocks/resets")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20220421134308.2885094-1-yangyingliang@huawei.com

Author: Yang Yingliang

drivers/clk/sunxi/clk-sun9i-mmc.c

@@ -109,6 +109,8 @@ static int sun9i_a80_mmc_config_clk_probe(struct platform_device *pdev)
 	spin_lock_init(&data->lock);
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r)
+		return -EINVAL;
 	/* one clock/reset pair per word */
 	count = DIV_ROUND_UP((resource_size(r)), SUN9I_MMC_WIDTH);
 	data->membase = devm_ioremap_resource(&pdev->dev, r);