mixer: simple: Support dB TLVs for CTL_SINGLE controls

alsa-project/alsa-lib pull request #358 was opened from marcan:

dB mappings do not work for controls not named "* Volume", since we do not fall back to CTL_SINGLE in get_selem_ctl. Add that branch to make it work.

Fixes dB ranges for e.g. controls named "* Gain".

Request URL : https://github.com/alsa-project/alsa-lib/pull/358 Patch URL : https://github.com/alsa-project/alsa-lib/pull/358.patch Repository URL: https://github.com/alsa-project/alsa-lib