ASoC: mxs: Fix error handling in mxs_sgtl5000_probe

In the Linux kernel, the following vulnerability has been resolved:

ASoC: mxs: Fix error handling in mxs_sgtl5000_probe

This function only calls of_node_put() in the regular path.

And it will cause refcount leak in error paths.

For example, when codec_np is NULL, saif_np[0] and saif_np[1]

are not NULL, it will cause leaks.

of_node_put() will check if the node pointer is NULL, so we can

call it directly to release the refcount of regular pointers.