cras-config: Fix a bug in parsing fixed digital gain

BUG=b:127952347
TEST=Manual test on Nocturne

Change-Id: I500464011104c1dbd0b7f0578713877793c4fe5d
Reviewed-on: https://chromium-review.googlesource.com/1512192
Commit-Ready: Hsinyu Chao <hychao@chromium.org>
Tested-by: Hsinyu Chao <hychao@chromium.org>
Reviewed-by: Hsinyu Chao <hychao@chromium.org>

cras-config/apm_config.cc

diff --git a/cras-config/apm_config.cc b/cras-config/apm_config.cc
index 407025b..bde4c41 100644
--- a/cras-config/apm_config.cc
+++ b/cras-config/apm_config.cc
@@ -51,7 +51,7 @@
 			level_estimator);
 	config.gain_controller2.adaptive_digital.use_saturation_protector =
 		APM_GET_INT(ini, ADAPTIVE_DIGITAL_USE_SATURATION_PROTECTOR);
-	config.gain_controller2.fixed_digital.gain_db = 0;
+	config.gain_controller2.fixed_digital.gain_db =
 		APM_GET_FLOAT(ini, APM_GAIN_CONTROLLER2_FIXED_DIGITAL_GAIN_DB);
 	apm->ApplyConfig(config);