audio:fix incomplete devices of duplicated output

When we get the devices of duplicated output by
desc->devices().types(),it will only return the
devices of suboutput1.This is because that the private
member mDeviceTypes of DeviceVector are not refreshed,
when merging two device vectors of suboutput1 and suboutput2.
This will cause some unexpected volume problems.

Change-Id: I9bc7551b3692d21ed7b49e2e93a685a75fef7fc5
Signed-off-by: wudongzhe <wudongzhe@xiaomi.com>