On an error, snd_ctl_add already free's kctrl, so calling snd_ctl_free_one
to free it again leads to a double free error.  Fix this by removing
the extraneous snd_ctl_free_one call.

Issue found using static analysis with CoverityScan, CID 1372908
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>