Since some jack controls may be renamed as phantom jacks, the existing
check for index conflicts doesn't work because it simply compares the
name with the last used name, assuming that the controls with the same
name continue.  Thus, it would result in the duplicated controls when
two or more phantom jacks with the very same type exist, and the
driver gives up with an error.

This patch fixes the problem by checking the index number conflicts
more intensively (but dumbly).
Signed-off-by: Takashi Iwai <tiwai@suse.de>