ALSA: jack: Fix the id uniqueness check

snd_kctl_jack_new() tries to assign a unique index number when a name
string that has been already registered is passed.  However, it checks
with the base string without "Jack" suffix, so it never hits.
Fix the call with the properly processed name string instead.

Fixes: b8dd0866 'ALSA: Jack: handle jack embedded kcontrol creating within ctljack')
Signed-off-by: Takashi Iwai <tiwai@suse.de>