ALSA: usb-audio: scarlett2: Move info lookup out of init function

The info variable is not used by snd_scarlett_gen2_init() except to
pass it to snd_scarlett_gen2_controls_create(), so move the lookup
into that function.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/c4b6d17708e104503d9a2b88f9b3320bb9904cfa.1624294591.git.g@b4.vu


Signed-off-by: Takashi Iwai <tiwai@suse.de>