ALSA: usb-audio: Add quirk for Pioneer DJ DDJ-SR2

Yet another quirk for Pioneer DJ DDJ-SR2, which is quite similar like
other DJ DDJ models but with slightly different EPs or channels.

Reported-by: Geraldo <geraldogabriel@gmail.com>
Link: https://lore.kernel.org/r/20201130083714.10640-1-tiwai@suse.de


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