Improve DAB radio support in refrence bcRadio HAL

Improved DAB radio support in the reference implementation for AIDL
broadcast radio HAL. Used real DAB service ID, ECC code, freuqnecy
and ensemble values for virtual DAB stations and implemented sub-channel
support for DAB radio.

Bug: 309693129
Test: atest VtsHalBroadcastradioAidlTargetTest
Change-Id: I6a78794e16400f05c6d7c5ec99aa4978adca5b58