libobs: Fix double -> float conversion warning

libobs/obs-audio-controls.c

@@ -313,7 +313,7 @@ static void volmeter_source_data_received(void *vptr, obs_source_t *source,
 
 	// Adjust magnitude/peak based on the volume level set by the user.
 	// And convert to dB.
-	mul = muted ? 0.0 : db_to_mul(volmeter->cur_db);
+	mul = muted ? 0.0f : db_to_mul(volmeter->cur_db);
 	for (int channel_nr = 0; channel_nr < MAX_AUDIO_CHANNELS;
 		channel_nr++) {
 		magnitude[channel_nr] = mul_to_db(