ALSA: scarlett2: Add Focusrite Clarett 2Pre and 4Pre USB support

It has been confirmed that all devices in the Focusrite Clarett USB
series work the same as the devices in the Clarett+ series. Add the
missing PIDs to enable support for the Clarett 2Pre and 4Pre USB.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/ZSFB8EVTG1PK1eq/@m.b4.vu


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