ALSA: usb-audio: Check mapping at creating connector controls, too

ALSA: usb-audio: Check mapping at creating connector controls, too

Add the mapping check to build_connector_control() so that the device
specific quirk can provide the node to skip for the badly behaving
connector controls.  As an example, ALC1220-VB-based codec implements
the skip entry for the broken SPDIF connector detection.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206873
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200412081331.4742-5-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>