ASoC: core: Fix Null-point-dereference in fmt_single_name()

Check the return value of devm_kstrdup() in case of
Null-point-dereference.

Fixes: 45dd9943 ("ASoC: core: remove artificial component and DAI name constraint")
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Link: https://lore.kernel.org/r/20210524024941.159952-1-wangkefeng.wang@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-core.c

@@ -2225,6 +2225,8 @@ static char *fmt_single_name(struct device *dev, int *id)
 		return NULL;
 
 	name = devm_kstrdup(dev, devname, GFP_KERNEL);
+	if (!name)
+		return NULL;
 
 	/* are we a "%s.%d" name (platform and SPI components) */
 	found = strstr(name, dev->driver->name);