ALSA: usb - Fix mixer map for Hercules Gamesurround Muse Pocket LT

Muse Pocket use brocken mixer names, so alsamixer and PA can't use it correctly
This patch add quirk to overwirte default mixers.

Signed-off-by: Alexey Fisher <bug-track@fisher-privat.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>