ALSA: hda - Add headset mic quirk for Dell Inspiron 5468

commit 311042d1 upstream.

This patch enables headset microphone on some variants of
Dell Inspiron 5468. (Dell SSID 0x07ad)

BugLink: https://bugs.launchpad.net/bugs/1617900


Signed-off-by: Shrirang Bagul <shrirang.bagul@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>