ASoC: tegra20_ac97: Fix missing error code in tegra20_ac97_platform_probe()

The error code is missing in this code scenario, add the error code
'-EINVAL' to the return value 'ret'.

This was found by coccicheck:

sound/soc/tegra/tegra20_ac97.c:357 tegra20_ac97_platform_probe() warn: missing error code 'ret'.

Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220701072850.62408-1-jiapeng.chong@linux.alibaba.com
Signed-off-by: Mark Brown <broonie@kernel.org>