ANDROID: usb: gadget: f_audio_source:replace deprecated API

Replace snd_card_create with snd_card_new.
snd_card_create depcrecated starting form v3.15

Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com>
Change-Id: I76f7d753812963d595055bce7d3e6518163482f5