Bluetooth: TMAP: Remove double definitions of TMAP roles support

Both the TMAP kconfig file and public header file defined
which roles were supported.

The Kconfig file options were recently added and were more
up to date (and correct), and allows for other Kconfig files
to use these values, thus allowing for more flexibility when
implementing applications.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>