ASoC: SOF: core: fix error return code in sof_probe_continue()

Fix to return negative error code -ENOMEM from the IPC init error
handling case instead of 0, as done elsewhere in this function.

Fixes: c16211d6

 ("ASoC: SOF: Add Sound Open Firmware driver core")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20200509093337.78897-1-weiyongjun1@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>