Fix the gap between mute and lowest possible volume. The es1370 mixer volumes were incorrectly calculated.
Fix the gap between mute and lowest possible volume. The es1370 mixer
volumes were incorrectly calculated.

I've tested this with one of my es1370 cards and I can confirm that it
works.

PR:		98167
Submitted by:	Joseph Terner <jtsn@gmx.de>
Approved by:	kib

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