CRAS: system_state: Adjust current gain when limit changes

When supported gain limit is changed, current gain should be updated
too.

BUG=chromium:673656
TEST=Use apprtc and switch between internal mic and headset mic. Check
cras_test_client --dump_s and see capture gain is changed to be within limit.
TEST=make check

Change-Id: Ia5f551d6d92fdb7cc90370f933664ae7db407008
Reviewed-on: https://chromium-review.googlesource.com/422709
Commit-Ready: Cheng-Yi Chiang <cychiang@chromium.org>
Tested-by: Cheng-Yi Chiang <cychiang@chromium.org>
Reviewed-by: Chinyue Chen <chinyue@chromium.org>
2 files changed