ALSA: scarlett2: Fix Scarlett 4th Gen 4i4 low-voltage detection

The value currently being read to determine the low-voltage state is
actually the front panel state. Fix the code to use the correct offset
for the low-voltage state.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Fixes: d7cfa2fd ("ALSA: scarlett2: Add power status control")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Message-ID: <d97b7d87f43b0e54f37e1552394be2f3ae182704.1710047969.git.g@b4.vu>